Yeah, but if I needed a raincoat, I wouldn't use any leather jacket. That would have nothing to do with veg tanned vs. Chrome tanned.
I'm just saying your experience of rain is pretty different from that of people in other places. Correct, a leather jacket is never a raincoat, but in many places you need to be ready for the possibility of unexpected rain (that's harder than anything in SoCal). The versatility is pretty crucial in most places.
And chrome tanned leather is inherently more water resistant.