Try this exercise: Hold your arm so a watch strapped on top of your wrist would be facing toward your eyes for easy viewing of its display. If you have a smartwatch, or any kind of watch, you do this many times a day. Now hold your arm in that position for 30 or 60 minutes to watch an entire TV show. You can take a break during the commercials. Enjoying that? Probably not. With a [smart]watch, you only glance at it a…
The use-case of it could be to primarily listen and just glance occasionally, like an augmented radio. News and sports events could fit the bill for example - listen most of the time and take a look for 30 seconds when something interesting/relevant is mentioned.
Also, sometimes companies do things just to show off their capabilities to the market, especially Japanese companies. Sony were the kings of this tactics back in the day.
As a side note, in the typical western FM band allocation (88 - 108MHz), the analog TV audio carrier for channel 6 would be located just under that (at 87.7MHz), and since most radio receivers could go a little under and over that range, most people could listen to channel 6 audio on the go.
This generated an entire market of "TV" stations who's main purpose was to broadcast audio, in the United States they were nicknamed "Franken-FMs".