(How) Can I use my Apple Watch Cellular to track whether I am at home or away?

So far Geofency has been great for tracking being at home / away.

However, recently I purchased an Apple Watch Cellular and now I no longer carry my iPhone all the time when I leave the house, but I will be wearing my watch (example: when I go running). Geofency also has an Apple Watch, but unfortunately that App cannot be used to track whether I am at home or away.

(How) Can I use my Apple Watch Cellular to track whether I am at home or away?

When I look at “Find my” on my iPad it says:

My location: iPhone X and mobile Apple Watches

(translation from my native language; actual English text might differ)

However, if I leave my iPhone at home (but am wearing my Apple Watch) I don’t get arrival/departure triggers (which I want to use in HomeKit automations). The triggers do work when I take my iPhone with me.

What am I doing wrong? Or is this text from Apple misleading?

I think the location of the Watch user is currently wearing is preferred. If my dad leaves for a run with his Cellular Watch and leaves his iPhone at home, the location shown for him in Find My as his physical location is wherever his Watch is.
If my thinking is correct, then shortcuts automatons should rely on that location of the user.
This I think is relevant only for iOS and Apple apps maybe. I doubt a 3rd party app can have continuous background location tracking privileges. Maybe there’s a way to do it with a watch face complication added (as it’s a little piece of the app that runs whenever wrist is raised). Maybe.

It might be for “Find my” only and not as Automation trigger? (No “When I leave home”)