OK, it definitely makes sense to me why you wouldn't TRADE a show that might be MP3 sourced, and I suppose I can see why acquiring a known non-MP3-souced version of the same show would simplify things in terms of not needing to separately track your tradeable and non-tradable collection.
I suppoose I just think people rely a little too much on spectral analyses and lose track of the forest for the trees some times. On DIME, I see shows posted with spectral analyses (to prove losslessness) far more often than I see shows with MP3 samples (which actually give a pretty good sense of whether the recording itself sounds any good). So many times I've wasted hours and gigabytes on certifiably lossless but lousy recordings.
"there is no reason in keeping MP3 sourced recordings when you probably can get the lossless version anywhere"
I wonder how true this really is for a lot of recordings. For example, as far as I know I was the only person to tape Bruce Hornsby 7/16/05 Reno, NV and Mark Knopfler 7/23/05 Saratoga, CA. Both recordings were made using AT853 > my Archos Jukebox recorder, which only records to MP3. The 7/16/05 venue was a little boomy but it was still a great show, and the Knopfler recording IMO sounds at least as good, if not better, than anything else circulating from the Summer 2005 tour (including the B&K 4011 Oregon show and the Schoeps Colorado show), but I've had to be very limited in circulating both, with lots of caveats attached. Still I'm sure both shows are now out there in many collections, not labeled as lossy, but if someone tosses out their copy after viewing its spectrogram thinking something better is out there, they are going to be disappointed.