Use Apple Watch instead of phone for location sharing?

See the 'Change your sharing device' section in:

Find friends and share your location with Find My - Apple Support

"To change the device that you're sharing your location from, open Find My on that device. Select the Me tab, then choose Use this [device] as My Location." So as I see it, open 'Find My' with your watch.

I don't think this is possible in the current software, and I am not convinced it is a practical plan if the Apple Watch is away from the iPhone and using standalone cellular. It is only my subjective impression, but I think to reduce battery drain the watch only updates location when there is a specific need like a polling query from FindMy, rather than continuous updates which are pushed out from the watch on a regular schedule. My guess is a standalone watch would have significantly reduced battery life if it was doing autonomous location broadcasts.

However, my doubts don't mean you should not submit it as a Wishlist item. https://www.apple.com/feedback/