What about a happy medium? Horsehide.
I have two Kramer Horsehide Belt Scabbards for my G19/23 and G30. They have a very hard Kydex like quality to them and they don't absorb water like cowhide. I suppose you could rinse the dust bunnies out of them with water, too.
The Kramer website states, " As a matter of fact, one group of operatives gave this rig, (the Vertical Scabbard,) the "ultimate field test" by immersing the gun and holster in salt water for 11 hours. The holster still retained the weapon."
I prefer to keep mine dry.