Their kidneys are super efficient, but that also makes them fragile. Kidney failure is the leading cause of death for cats. It’s better not to put them under unnecessary stress.

Well, it doesn’t. Kidney failure is the leading cause of death for cats. So much so that a Japanese professor is working on medication to improve kidney function in cats, which is expected to double their lifespan. Source

Cats are desert animals by origin and they have super efficient kidneys to retain as much water as possible. This also makes them much more fragile. Compare it to a highly tuned racing car, when you push it to the limit you get the most performance but also get more wear on the parts which reduces the lifespan.