If you mean just digital money (e-money) than yes. In not-distant-future this e-money can replace physical cash. But it can not be replace with e-currency/cryptocurrencies.

The e-currency value it self is not stable, more like a stock in market.

If you are talking specifically about blockchain-based cryptocurrencies, it is unlikely that public, decentralized cryptos such as bitcoin will become cash replacements any time soon - because of government regulation, tax implications, and price instability. However, some governments such as Russia and Venezuela (among others) are experimenting with the idea of a state-backed central bank issued cryptocurrency for use in those countries.

If that happens, then yes, these would replace physical cash in many instances.

Even it can be possible through your fingerprints without carrying any credit/debit card.

Adam Hayes! It seemed that anyone could buy or sell anything with Bitcoin and never be tracked and it’s totally anonymous either not KYC (Know Your Customer) approved???

Bitcoin, it turns out, is not very anonymous and forensic analysis can reveal identities of transactions many times. Because of this, users of dark web markets have moved away from Bitcoin into other, more anonymous cryptocurrencies like Monero and ZCash

Digitisation of money or e -currency is banking reform which is taking place almost in every economy and would definitely render ease in time or cost aspects. In India too more schemes like UPI ( Unified Payment Interface) are introduced for successful implementation of "Digital India" but this is not the case with crypto-currencies, bitcoin, ripple etc. with any nation as it's policies are opposed of central banking system.

I also agree that the circulation of existing currencies is going more and more digital. Moreover, this phenomenon is supported and stimulated by governments worldwide. The reason is obvious - it will make it possible (in its final no-cash stage) to control all the financial activities of whole societies. Big Brother is watching your wallet. "Anonymous" cryptocurrencies are in contradiction with that goal.

But there's one more problem. The advantage of physical cash is that it is usable off-line and even without any supplies of electricity. the only condition of finalizing any cash transaction is that its both parties accept the validity and value of the cash involved. Electronic money need technically complicated infrastructure, both electronic hardware and software, and on-line connections for authorization purposes. What to do when this infrastructure fails? Of course, it can work to some extent without on-line connections available non-stop. Some transactions may be performed off-line - I mean e.g. floor limits for payments cards or even money "stored" totally off-line like on cards for public payphones.

Especially small transactions like buying snacks and drinks in vending machines, paying for parking time or public toilets can be performed off-line without much risking frauds. But cryptocurrencies (at least as far I understand how they work) cannot be used off-line.

In my opinion, cryptocurrencies don't have any essential advantage to compare both with physical cash and the electronic circulation of existing currencies.

Well, to put it very simple, we can classify the financial transactions into two types, Physical world transactions (actual fiat transactions) and Digital world transactions (cash less transactions). Many people getting confused because they see financial transactions as a whole and forget the types of transactions. Cryptocurrencies are here to replace the digital world transactions and not physical world transactions (atleast not anytime soon).

Bitcoin and other cryptocurrencies which only serves as a transaction of financial value will be restricted from usage in near future. But cryptos which servers more than just a transfer of financial value like Ethereum, NEO, Stellar etc. will thrive as a platform. Sooner or later governments will have their own cryptocurrenceis backed up by their fiat currencies Example: USDT (its not backed by the government though ). Russia, China, Britan and more countries are trying to create their own currencies and other will follow soon.

If you are an investor, its better to invest in tokens which serve more than a currency.

Manoharan Ramachandran , you gave a very interesting comment. If cryptocurrencies are considered as a platform rather a carrier of value with no physical form, then you are right. The word "currency" in "cryptocurrency" was misleading to me. It made me think of cryptocurrencies mainly as money with no physical form like SDR, ECU (the cashless predecessor of euro) or clearing/transfer ruble (cashless currencies for clearing the international trade within the former Communist block).

And my doubts were expressed because the initial question was about possible replacement of physical cash with cryptocurrencies.

@Manoharan Ramachandran:

I see the value of Bitcoin for investors as less critical for the following reasons, because there are also additional benefits to the normal bitcoin trade:

1) Third-party use

Many services pass their data through the Bitcoin blockchain, e. g. http://coloredcoins.org or the University of Nicosia as a forgery-proof proof of issued degrees.

2) Security

The Bitcoin network is the most secure in the world, so it is very likely to be used for the transmission of large values.

3) Awareness level

Bitcoin is the most popular cryptocurrency and blockchain application.

4) Network effects

The benefits of the Bitcoin network increase squarely as the number of users increases. This means that the network has a quadratically increasing value as the number of users increases. It's like Facebook, Google or WhatsApp. If only a few people were to use it, the benefits would be rather limited, with each additional user the benefits increases, which is why the networks today have a high value. It is quite likely that today's scaling problems will be solved in the foreseeable future (exchanges, sidechains, lightening network...), then the benefit and value will increase significantly.

5) Needle eye Bitcoin

The Bitcoin network is also used in the trading of most other cryptocurrencies, as only the fewest cryptocurrencies can be bought directly with Euro or Dollar. The trade takes place very often via Bitcoin, for which Bitcoin is valuable.

Central Banks are currently demonetizing or reducing the carrying overhead burden of physical cash. Its actually very difficult and costly to manage.

If we should do some future-scoping, can we imagine there being hordes of physical cash cash in 2030 or 2040 ? Not very likely.

The IMF Chief shared such a vision with the Bank of England recently.

https://www.imf.org/en/News/Articles/2017/09/28/sp092917-central-banking-and-fintech-a-brave-new-world

UPI payments at record high in July

• Data released by the NCPI show that UPI payments recorded 1.5 billion transactions in July 2020, the highest so far

• The number of transactions jumped from over 999 million in April to 1,497 million in July 2020

https://blts.app/10284