Yes, thats true. UNO, Micro and Nano are the same processor, but with less peripheral. Mega with more memory, DUE with a 32 bits processor, etc.
I work with them but don't use Arduino language. I use C, C++ and Assembly. The advantage is the quantity of low cost peripherals and librarys for them.
Greetings Omar A. Imran , we can create board Arduino by our self using DIP size atmega328p, it's very small controller, we can use it for renewable energy embedded system. it's opensource . i think it's very use full for our projects.
Adruino encapsulates much of the hardware from the programmer, therefore allows easy option to implement embedded systems, for various application. It has become popular for many IoT applications, such as real time monitoring of various physical parameters, etc.
Many communications protocols with applications in automation, Smart city industrial systems and Robotic : To make direct contact with the Coronavirus patients.