Water resistant is not water proof.
The real world is analogue and not a binary on/off setting you click in a config file. "Make this thing indestructable"
There is an infinite sliding scale from normal air humidity to the corrosive wetness of a tropical rainforest near a saltwater ocean or the difference being splashed with a few raindrops to being submerged for 100 years at the Mariana Trench.
Pure not salt water or tap water, not contaminated toilet water where most phones seem to end up. And only for a certain time at a certain depth (pressure). And not pressurized just static.
Maybe they should be named USB-Sea? /s
I agree it's resistant and it does what you say... But the way they advertise it....