Most smart watches don’t have a physical SIM card slot since that would be way too big. The software used to load an eSIM onto the watch often has a whitelist for carriers.
Another issue is that both the watch and the phone need to share a phone number if you want to leave your phone at home and answer calls and receive SMS on the watch. This isn’t standardized and only works with each watch’s supported carriers.
Another issue is that both the watch and the phone need to share a phone number if you want to leave your phone at home and answer calls and receive SMS on the watch. This isn’t standardized and only works with each watch’s supported carriers.