I have always-on display turned on. So the screen is always showing something, just not anything important, like the notification I just got, or the next turn on my navigation route, or whatever.

If you ever used a watch that did show notifications automatically with an always-on screen and then went back to one that doesn't, you would probably notice that it's way slower, and also there are many times where you can see the watch screen but it's not convenient to do a gesture.