Tony, that gives you a seat over the water but you can only soak your feet or use an over bath shower. If somebody is very disabled and needs to be washed, then they are useful but they don't give the user a bath...and again they need to be cleaned often and allowed to dry off. If you had seen the yack that accumulates under some of them :(
OK woof my mistake thought it was low able, but my partner Jen got stuck in bath earlier this week, only my threat to call ambulance managed to get her on her feet.
If you want one that goes up and down, you want a bath lift and yes some of them swivel. Again they need frequent cleaning and allowing to dry and anyone else who uses the bath has to be ok with using it too because they are not an easy lift in and out. Same advice, find a shop, have the user try the seats out and then go home and think. Take into account the cons as well as the pros.