We had On-Star on both our vehicles when we purchased them new. After the trial, we let it die.
Then we were somewhere in Tennessee at a very remotely located diesel-gas station. We were all outside the truck and our SmartPhones were inside the cab, windows rolled up when "it" happened!
Dog stepped on the door locks and locked all the doors! Panic! Shock! What do we do now! We're in the middle of no where and all the keys are inside the truck. We couldn't even access the trailer. And we're parked in a fuel pump bay.
My adult son was with us, and luckily, he had his phone in his pocket. We were able to finally call OnStar after going through hoops, and they remotely unlocked our doors. While we had the representative on the line, we renewed our On Star subscription right there on the spot! We carry just the basic minimum so we can unlock the doors with our SmartPhones if it ever happens again. We went ahead an kept it for the car too. It's kind of nice when one of us is on our way to or from work, the other one can track where the vehicle is with the map/gps system. And it's nice to start the truck (diesel) in the winter when I'm at work and let it warm up before leaving the building.
We decided the On-Star WIFI Hot Spot, or whatever it is was not worth it. Like you, we have all that capability with our SmartPhones, we don't need internet access via the vehicles. It's an extra cost and since we have it on the phones anyway, it did not make sense for us.
Because we do a lot of work from home, we finally went with an unlimited data plan for our phones, and for our purposes, the phones and the phones hot spot for our laptops and I-pad and traveling has worked very well for us.
For only a few dollars a month, it IS worth it to be able to unlock your doors if you leave your keys inside (or the dog steps on the door locks)!!!!