Need clarification on Watch app - can it work standalone without a paired iPhone?

[sneakinhysteria]

My testing is inconclusive. I used to have on-device actions and it seemed it worked without the phone. I then switched to synced actions and now it seems to need the paired phone to connect to my HA server. But maybe this is just guess work and there is some level of settings caching involved. It would be great to understand from the devs how this is currently designed.

To make matters more confusing, I have switched to a Tailscale setup for secure remote server access and now the question of how my watch can access my server on its own remotely pops up again.

A related question is if the HA Watch app uses an existing cellular connection or only works on Wifi.