I think there is a bit of a spectrum e.g.

- I don't want EVERY SINGLE notification from my phone to go to my watch

- I also don't want zero notifications b/c it's very useful to get notifications from my kids, important calendar reminders, my boss sends me a slack etc

Also, the watch allows me to still be "connected" for important events but not distracted by my phone.

(I should add that Apple watches give you a LOT of control over the notifications from your phone to your watch. Not sure if that's true with other watches)