Maybe if your main use case is as an activity tracker, you’re probably right. But for me it’s a phone extension.
I think Garmins are mainly sport watches with some smart features and the Apple watch is the opposite.
Calling someone using siri, or doing things with siri in general are features I use all the time.
Apple watch for me is a phone that I can use when cooking and taking care of a toddler at the same time without ever touching it. Garmin simply can’t do it. Alexa is not that great and the general integration is obviously not as good as Apple.