I would sleep or rest in one eg in between delayed flights.One such hotel has been built at one of the London airports.Age means for the moment I have forgotten which one.
It certainly beats trying to sleep in a chair, on long layovers or delays.As a permanant base for exploring a city, no.
My brother used to use one in Tokyo when he was too tired to go back to his house.He has since got a small appartment in Tokyo and spends the week there and weekends at his house.He is 6ft 4ins and said, as a cheap place to sleep, they were perfectly adequate.Certanly beat sleeping in his office after a long day.