Thank you for merging with the existing thread.
You’re right - for my use case it would be absolutely fine if it just put a dot on the map every ten seconds. If the page wasn’t getting GPS data because the phone was locked or the browser in the background or whatever, then just don’t put anything on the map.
I think that would be better than “joining the dots”, resulting in straight lines between available data points.
Looks like the W3C Sensors group recently agreed to try to progress this for the geolocation-sensor API, but I’d guess an actual implementation is years away, and would require a PWA.