Many times, companies set up different entities in different jurisdiction to benefit from the tax policy in that country. Companies such as Google, Facebook, Apple follow such practise to ensure they can provide their shareholders the best return.

Divide & Conquer - Instead of putting all your "eggs" in one basket, spread them out into different entities to manage the risk. You never know what sort of issues you could run into in a new market.

Certain markets or country require you to have local presence before you can sell or generate revenue from that country so setting up your company in these country to overcome such situation is a practical solution.