I'm not sure I agree with less intrusive. Having a tracker attached to your body that can notify you of anything it wants is very intrusive. It is, however, seemingly less addictive in some capacities. No doom scrolling, etc.
Whereas on a phone, the temptation to open apps to do things is always there.
It's almost like comparing an eink device with a regular tablet.
Also, almost every smart watch allows you to block notifications on top of what you phone already blocks, so if you have apps that you want notifications from for when your attention is on your phone, but not all the time, you can only allow those through. It's not "anything it wants", it's anything you choose.