If their corporate taxes are lower than in your country (after calculating for what you have to pay according to the double taxation agreement the two countries have) then it's worth it opening your company there.

Depends on how high the corporate taxes are in your country. If it's worth it, the big advantage is that everything can be done online.

You can setup a company and base it from there. You can be in Timbuktu, Ulaanbatar, etc and be running a European company trading with parties all over the world. There are probably other benefits but that one clinches it for me ;-)

Not much, really. You can setup a company remotely, only to have to come to Estonia anyway to try to open a bank account and most likely get rejected.