Honestly, from the outdoorsy type of hiking apparel I've invested in during the past few years, most of my casual clothing is fairly waterproof, and I don't need to worry much about incidental rain on me.
However, if I'm dressed for church, with a button-down cotton shirt, slacks, and a matching hat, well I'd better take measures to protect that.
It's really weird in my urban environment, where it is simply assumed that everyone owns a private vehicle, parks in the parking lot, and drives around in a climate-controlled, dry, private bubble. Nobody in their right mind walks into church off the streets!
When I grew up in CA, my grandparents had a home designed by an architect from the Midwest, and it showed. One of its features was a "Mud Room" on the side: a private entrance for family and close friends only, where folks could don/doff their raincoats, snow gear, muddy boots and other stuff, leave it in there, and enter the house without tracking it all inside. Buildings in Phoenix simply don't have those amenities. They don't even have hatracks or coatracks here: you just leave it in your car!