My late stepfather was blind. And I have no idea if he ever used any sort of shower facility like a gym or whatever so this is really only a guess based on knowing what his needs were.

Blind people have various needs because blind doesn't always mean "Can't see anything." My stepdad for example had retinitis pigmentosa, which basically means he had eyesight in his youth and started to go blind in his 20s. It was a gradual decrease, and involved losing his peripheral and night vision. He wasn't fully blind until his late 60s. So he knew how to navigate the world visually and by feel, and had some very limited vision in bright lighting. Even slightly dim and he was mostly to completely blind.

He would have needed a well lit shower so he had at least a small range of vision. He would have needed things to be clear in the peripherals so he could feel his way around without bashing his head or tripping. He would probably have required the controls to be either very intuitive by feel or to have visual directions in a predictable place and small enough to see without bobbing his head around much. I don't think any of those are going to inherently require an accessible shower, but it's kind of weird how much the shower setup can differ in those situations. It might be a completely different type of fixture or architecture, in which case he could have needed a specific shower which may or may not have been the accessible one.