The better wet rooms I have seen in scandinavia, are large enough to NOT splosh water on the way to the exit doors.
This, plus good heating, keeps the water where its supposed to be.
The use of wooden fitments is u to te individual and whether r not the room is liable to be used by small children who want to[play 'shower fights' and splash everything. We have an oak door that gets liberally doused every time the shower is used in one room,but it actually shows less problems than exteriors doors. It dries rapidly and the AVERAGE humidity in that room is very low.
It seems that what is an issue is *prolonged* high humidity and dampness (and UV!) which leads to swelling and rot.