Re: I'd go further than that personally
I really like being able to check and screen notifications with a glance at my wrist regardless of where my phone is, and there are plenty of circumstances for me where the phone is not in handy reach and I use notifications a lot. And as you say, it also happens silently - I've had no ring tone enabled for years. Others may not see the benefit, but that's to be expected because we are all different though some people do feel that the centre of the universe can be found at their centre of gravity therefore they will never understand that other people do thing differently, in their mind all smartwatches must be pointless.
I don't think anyone said they need to be "compelling", because thinking about it, even the smartphone itself isn't compelling. They are just handy little benefits.
I still wouldn't go for Apple's interpretation though, just a very cheaply acquired Pebble Time does the useful stuff well and for my requirements pisses all over Apple's offering.