I had one in Chile. It was in sort of a conservatory. I've no idea what the running costs were but I bet they were huge. The thing was a complete PITA. I can also tell you that putting bubble bath in them to see what happens is a significant mistake.
There's also one in the ski lodge I use which is equally pointless.
It's not much better than a bath, just bigger and for more than one person. It takes a ton of maintenance and gets dirty if you look at it wrong.
I really see no benefit in them at all.
Now saunas on the other hand........
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