As noted before, these LTE-compatible watches will share phone numbers with your phone, but pack all that's necessary to work even when your phone is far, far away. As long as both watch and phone can connect to your carrier, LTE Android Wear devices will be able to send and receive messages, Google things, and run your favorite apps.
Taking calls is also doable if you like talking at your wrist. Google's own announcement highlights marathons and errand-running as examples where you might leave your phone behind, and as smartphones have expanded in size, for those of us that Must Be Connected At All Times, an LTE wearable might fill the gap nicely. AT&T starts selling the LG watch online today and in-store this Friday, while Verizon subscribers will be able to preorder starting today.