Each country in Windows Phone Store can have its own store description , screenshots and keywords , But is it worth to localize your app in so many languages ?
It depends on the complexity of the App. If its Simple and Readable to understand not worth the effort. People can easily understand from description and snapshots.
It depends on what type of app you have. Sometimes it helps to localize all the way to your keywords. There are still many people that will search the store in their native language(depending on what they are searching for). Such localization makes it easier for them to find your app.
I think it's worth the work. But only if it's done well. An app translation with google translator normaly isn't so well that I would consider it as an option. I prefer to have an english app than a bad localized german. At least if you don't have an option to change your language manually to another language.
Depending on the store information. I would translate keywords and description. For the Screenshots I used everywhere the same.