[yason]

I really wonder what per-country work is needed really?

There's internet! Money bounces back and forth over the internet already. People have credit cards. What is it that Google has to do to let me sell and buy Android apps in one of the unlisted European countries that I live in?

[lsc]

VAT and other tax weirdness. generally speaking, if I (based in the US) sell a product to someone in, say, japan, absent any tariffs, I don't need to pay any taxes. But, if I have a business presence in japan, I've gotta pay Japanese sales taxes on that.

It's all more complex than that... but yeah, doing business in other places usually results in tax weirdness.