Man, I can't even imagine wanting to bring my phone into the shower. "Just standing" there, alone with my thoughts, hot water relaxing muscles... Nothing needs me, I need nothing, the world is on hold until further notice. It's meditative: Everything ceases mattering, ceases even existing - to resume later, of course, but in the meantime, perfect, relaxed, complete solitude. It's perfect as it is. Music or videos or reading would ruin it. That's all outside stuff, the outside should not exist.
It never even occurred to me that people would bring phones into the shower to actually do things. Never even imagined that that was a thing. Learn something new every day.