I wonder why ODing is not a problem in rest of the world. If I were to guess it's to save money and not becuase they were concerned about some random dude ODing.
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.