As a ham radio operator, I’m quite familiar with push-to-talk communications, and there are many situations where it is extremely convenient and possibly the best communication method. For example…
Casual intermittent conversation, like friends might have if they are in the same room, but aren’t. While a phone is great for continuous conversation, the Relay would be far better for occasional random comments.
Driving in a caravan/convoy. Less distracting to use, and again, the medium readily lends itself to intermittent bursts of chatter with longer quiet periods in-between, yet can still be comfortably used for a “real” conversation when needed.
A family or group of friends can easily keep in touch at a campsite, while hiking or biking, or at a shopping mall or theme park. The small size and wrist-wearability is more convenient than having a phone or radio clipped on a belt, and the range is virtually infinite (as long as you’re in reach of WiFi or Cellular signal, of course, but some sort of peer-to-peer capability might be nice to add, if possible, on the next generation - hint, hint).
Would make for a super-cool doorbell button - answer your door from anywhere. Would even work for full-time RV dwellers, who might not have the internet access required for traditional “connected” doorbells.
I want to get at least two, maybe three, to explore some of these possibilities - both as a substitute for handheld amateur (or FRS) radios when greater distance coverage is needed, and for experimenting with “alternative” uses for RVers and travelers.