I think one other consideration with Bandcamp is that it allows music to be released that may not otherwise see the light of day. We've all seen CDs on merch tables that were pressed in a run of 1000 or whatever five, six, seven years ago and haven't sold out yet. The market for improvisation is healthy but not huge.
Now good quality digital recordings can be made at reasonably low cost it's great to have a way of releasing more material without having £££s tied up in boxes of CDs.
I always prefer physical product but Bandcamp seems like a good option for music we might otherwise not hear.