I understand that the spool can't turn once it's clipped into the line, but nothing is then keeping the line from unspooling except tension. If you, for example, ran the line around a placement to bring it in at a right angle, and the line slipped off the placement, that tension would be gone, and then nothing prevents the line from unspooling just from its weight. Also, you still have to clip it to store it in a pocket, right? So you don't get "rid" of a clip.
I dunno. Maybe this is a great gadget. I love my little Dive Rite jump reel, and I know people who would say that's not necessary, either. But I want to hear some feedback from people who buy this before I get all excited. I bought a Spreel, years ago, and learned to my chagrin that that wasn't a good idea. Spools are just darned simple, which is the best thing about them.