Sure, there's a market for it. Really, absolutely no surprise here.
There was already a quite popular German-based (free) theme directory around 2006/ 2007. That was discontinued for a lot of reasons (as of my knowledge), but surely not because of language-based reasons.

I hope this new shop will be a success and many more language and/or niche-based shops to follow!

Congrats to all behind this initiative! :)