I answered that elsewhere, so lemme just cut/paste:
Fair question: I saw they already had a partial spindle of mixed disks for sale. Just the one though, so I couldn't be sure it wasn't a fluke. Turns out it wasn't.
The spindles weren't the only thing I donated, just so we're clear. I just mixed them in with the rest of boxes of stuff, some of it pretty good. Someone can now snag an OG release copy of Bioshock 2 or Doom 3 for a song. Oh, and the entire Half Life Collection.