My experience is primarily with ball pythons so I wouls say they are fine in racks.
Now other kinds of snakes may have more of a need for discovery or visual stimulation.
My thought is it depends on the kind of snake we are talking about and what sucessful keepers of these snakes have found to help them thrive.
Ball pythons spend much of there life in small burrows and are very shy so I would say they are great canidates for tubs and they seem to thrive in them.
The key is to think of the animals comfort/personality and not ours.
