Not sure about the super-high gap ones, but I'd bet the normal-gap (mid shin, maybe?) ones make cleaning a lot easier. A semi-permanent pre-fab wall especially is probably gonna have a lot of gross little nooks & crannies at floor level. Also means you don't need to match the walls to the room height, which probably makes them a lot cheaper.

I mean, imagine mopping one of those rooms. Bet you'd immediately be glad the partitions didn't reach the floor.