Yeah, my Garmin (an Instinct 2 Solar) has ruined me for other smartwatches. I appreciate not having to think about charging it in the summer and only monthly in the winter. I appreciate the reliability of an always-on screen rather than one that usually turns on when I turn my wrist. I appreciate the consistency of buttons that I have learned by feel rather than fiddly touch/voice controls that usually work the way I want.
I'd consider upgrading it someday so that I don't need to bring a phone for podcasts or ad-hoc navigation, but only if those do not come at the expense of battery life, always-on screen, and physical buttons.
(Edit: I'm glad other devices with different tradeoffs exist for different kinds of people though!)
The biggest benefit of a smartwatch with a fuller OS is that it can give you more data. On my watch face, I have the weather, the AQI air quality rating, and the UV index. I'm outside a lot, so this is real-time data that I find very helpful to have be glanceable.
I have the weather on my watch face as well, though I do have to drill into the weather widget/glance to see the air quality index and UV index. Skimming the Garmin Connect IQ Store it looks like I could add those metrics to my watch face if I install a 3rd party data field or widget.
I will admit that I haven't installed very many 3rd party apps and my subjective impression is that many Garmin users never end up using 3rd party apps. The apps also look a bit utilitarian compared to Apple Watch apps. Still, having tried various kinds of smartwatches I definitely prefer a wearable that acts more like an appliance than a wrist-mounted computer.
You can have all that with the Garmin watches as well. They keep constant Bluetooth connection with your phone and can display realtime weather/ air quality/ etc on the always-on display.
I'd consider upgrading it someday so that I don't need to bring a phone for podcasts or ad-hoc navigation, but only if those do not come at the expense of battery life, always-on screen, and physical buttons.
(Edit: I'm glad other devices with different tradeoffs exist for different kinds of people though!)