>1. Your fingers change size and rings are not adjustable

....I guess OP doesn't wear a wedding ring, or any other kind of ring for that matter? How is that a problem with the smart ring, specifically?

I have a gold wedding band and can have it resized if needed. Also, I don't wear my wedding band when exercising, and that doesn't reduce its utility for me much. But a health tracker ring is arguably at its most useful when worn during exercise, to having to take it off while working out is not great. This isn't limited to weight lifting, as others hav noted. It also applies to tennis or other racquet sports where it gets in the way, and to anyone whose hands swell significantly during exercise. I find that even long walks make my fingers swell quite a bit. So I'd either have to get a ring that's loose during everyday wear or take it off during intensive exercise.