I'm puzzled by this thread. For me the question is: "Am I happy to make a sale, am I happy with the price I get?".
If someone else is shrewd enough to find a buyer for the same item and successfully get a higher price, at most that's a lesson for me next time around.
Copyright? Of a listing description? Aw, c'mon, we're not talking about a Harry Potter best seller here, complete with film rights!
If someone else really likes my description that much (and admittedly I do put some effort into them), well, imitation is the sincerest form of flattery!
I hereby grant all of you the right to buy any of my items, reuse photos and/or my description (as long as it still applies to your own ownership), and make as much profit as you like! However, if in the description I say something like "This item was owned by my great aunt who bought it in 1927...", I would take umbrage if you copy that verbatim. Unless you're a cousin of mine!!