They don't really do the job of a regular smart watch and aren't designed for wearing all the time, so it becomes a secondary device you need to manage and charge separately, not to mention pay for. Meanwhile, an Apple Watch can do all of it.
IME, the battery life of Garmin's isn't a game changer... if you're using GPS (which for me would be all the time I'm using it), you're still charging regularly. Might as well charge every time you take it off. Not quite daily, but in the same ball park.