For most of my waking hours, my phone is sitting next to me on my desk, couch, or table. Carplay has my back when I'm driving. I honestly don't miss any of the notifications from my smart watches.
It's also a hassle to have it "read" messages, it requires far too much interaction with the screen (and then the phone for permissions) for driving.
In contrast, with my Pixel watch, while driving, I can see enough of the message to get an idea if it's important or not.