Strava supports recording your run without the phone but will not upload the results without the companion app. It drives me nuts.
It’s impossible to call a Lyft, Car2go, or electric scooter from just the watch. Uber still has a watch app but I won’t support their business.
Text messages may choose to go to your watch … they might go to your iPad or Mac instead. There doesn’t seem to be a clear pattern.
The Washington Post app just won’t refresh without your phone. LTE be damned.
Surprisingly, this is a short list of complaints and the Messages issue is the only one that is serious. For me, it’s almost a complete phone replacement.