International publication is preferred over local publication of research articles. Such publication has relatively more peer exposure and is generally free from likely local bias.

The difference is basically of visibility. Publishing with an international journal means you are reaching out to millions of experts. Most of the local journal are not indexed, a factor that directly affects the readability or impact factor. The more you publish with an international journal the more you let more experts know your work.

1- Yes

2- Most of the time, the answer is YES. International publishers have a wider community with much more readers worldwide; while most of local publishers do not have as they are restricted to a small area or community. Further, most of local publishers publish in local language while the international publishers use English. Accessibility and readability to those international publishers are quite better. A paper published by an international journal/magazine is accepted internationally while those locally published ones are not. International journals are evaluated and ranked by different resources, like impact factors provided for all ISI journals provided by JCR. Such ranking is almost always not available for local journals, especially those published in a language other than english.

3- As I said some of them above, there are a lot of advantages publishing by international publishers.