I'd prefer sportsbook for now over betting exchanges only because I haven't tried using any of those good betting exchanges the only one i've used so far is fairlay and I agree the experience isn't the best but you do get some pretty good odds.
I do not really know the difference between the two, but the crypto exchange example makes this sound like player vs player platform or something similar. If such exchanges don't mind your winnings, it's probably because you are not betting with them. I guess that type of betting exchange is not very popular due to lack of adequate players on regular basis
Betting exchanges are popular from my experience it's rare that your bets will never get matched. I think there's not much betting exchanges when compared to sportsbooks is because their profits are limited due to having the best odds.