A:Answer It will work perfectly fine if your phone is with you or I mean to say close to the watch. But after certain distance watch and phone loses connection with each other. That is when you cannot receive calls or text anyone, but all other features, specifically Fitness features, Blood Oxygen EKG act. everything works fine. Getting cellular connection make it little convenient for you when you are running in your community or working out because you don't have to carry your phone with you. You can always download music on your watch upto 200mb for workouts or on the go. But if you have cellular connection you can steam Apple Music unlimited. Again, it is your choice. There is a wifi model that works exactly the same way if you don't have cellular connection on your watch. I bought Wifi model then returned it to get the cellular one, just because I didn't want to carry my phone with me all the time specifically when running. The main goal is fitness, having a cellular connection keeps you in touch with 911, or family members in case of emergency. (if your phone is not with you)