I have no idea if the Kobo store will work in Taiwan. Geographic restrictions suck and exist for all of the book stores. I don't know how easy it is to get around them at the Kobo Store. I know Amazon is easy to circumvent and Barnes and Nobles can be circumvented but you have to work at it a bit more.
I do know that the Kobo is meant to be an international reader but it has not been released across the globe. I believe it is available in the US, Canada, and Australia. There may be other countries that I am not aware of.
The Kindle is sold to Taiwan and that you can buy books using the Amazon store. You will not have full access to the US store but you can circumvent those barriers pretty easily.