I thought it was that the jets of water (sprayer) increase pressure and are actually harsher in some ways vs submerging ?
And of course high heat melts the glue (like hot tubs)
It’s more than one thing but the surfactants are pretty bad.
Interesting. I've seen people wash their phones in just simple soap and I've done the same many times. I only use pretty minimalist castille soap though. Figured that would have the least chance of damaging the oleophobic coatings