Why did some shows tape such an obscene number of pilots? Aren't those things kinda expensive?
Well, overwhelmingly, the cost is in creating the set and gathering everybody together. Once you've done that, making additional episodes isn't a lot more expensive, especially if you're shooting it all on the same day. Besides, especially in those two examples, you're probably looking at what we would more accurately call "test episodes", even if they were all called pilots on the slate. A pilot is usually something the network gives you money to make, and a network isn't going to ask you for ten episodes in order to make up its mind.
I've seen multiple pilots shot for very specific reasons, such as trying out different hosts. But in the cases you're describing, it sounds like they're just trying to work bugs out on a full set. Bean, as we've noted, seemed awkward in a host's role, so it's somewhat logical to guess that part of Concentration was giving him the chance to get comfortable doing it for real.