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’ve used one for podcasts, definitely. But even for music, they may be poor quality generally but they’re significantly better than a phone speaker, and much better than a phone speaker ten feet away through glass or plastic.