At this point Apple ships an LTE connected smart watch. Android OEMs have done so for a few years at this point. So I think all that remains is for costs to come down, battery life to improve, and the social acceptance thing to play out. I think smart parents will be giving their kids smartwatches instead of phones in a couple of years (smarter parents will not give their kids either, but I digress...).

> smart watches are peripherals, not communications devices, right?

The most popular ones in the US are, but ones that are fully independent phones with their own SIM have been available for some time.

Just for some examples: https://www.smartgeekwrist.com/standalone-smartwatch-sim-car...