Perhaps the recipient is afraid of offending you by saying that it's not something they can make use of. Perhaps rather than leaving it unused until discarded they have decided that someone else could benefit from it, and they could find the money more useful. Perhaps they never considered that you would spot it for sale in the classifieds.
But only perhaps.
And just make a mental note never to give Céline Dion CD's as a present to anyone again :D