Seems pointless and inconvenient for me as they usually seem to be poor quality, and can you really listen to music in the shower, and are you showering long enough to benefit from it?
Or do you own one and use for a different purpose, like swimming or Kayaking?
I find the main issue is that for it to be loud enough to be clear over the shower (audiobook) it has to be loud enough that I worry it’ll annoy my neighbours upstairs/my flatmate