I've been doing this for around 10 years, have very hot, steamy showers and never had a problem 🤷
Started with the Samsung Galaxy S7, one of the earlier water resistant phones, and I've been doing it ever since, across maybe 5 phones, almost every day. You'll be fine. If you are worried about drops, just use a decent case.
As for why, others have said, it's to keep listening to my YouTube video essays and similar. Stuff that doesn't need to be seen to be appreciated.