Yeah, it's smart.
Because the main reason books in English don't sell well in Germany isn't because Germans don't read a ton of English books -- it's because they're not easily finding them on the Amazon.de site because books in English on the Amazon.de site are using the keywords that we put into the Amazon.com site (unless you do Darke's trick and upload them separately with distinct metadata). And those Amazon.com keywords are NOT very effective for reaching a totally different foreign market on the Amazon.de site. *raise your hand if you followed that, you get a blueberry vanilla swirl sucker*
Sort of a digression, but we have a partner who's been experimenting with publishing books on Amazon.es.
Interestingly, he said one of the biggest barriers is that Spaniards A) haven't adapted to ordering online with frequency and urgency the way that Brits and Americans have (some of that is obvious economic differences) B) Spaniards absolutely do NOT use their credit cards for $1.00 purchases. That's a completely foreign concept in Spain -- charging a one dollar purchase on a credit card.
That is a huge cultural difference -- and a distinct sales barrier.