After working wireless retail in the early '00s, I will always choose a phone with a high IP rating. Other scenarios I've seen - Phone pushed into sink without realizing while doing dishes and walking away for an hour long phone call, parked convertible with phone in the cupholder, boob sweat, working in a greenhouse going in and out of air conditioning, leaving on a picnic table overnight while camping, water bottle leaking in purse, etc. Also there's utility in feeling confident the phone can survive if you need to wash syrup, baby food, sticky bar residue, etc off it.