A spare key stashed will accomplish the same thing.If you lock yourself out of your car, On Star can open it for you. Cell phone can’t without an app. And if you lock your phone and keys in the car, you can borrow someone else’s phone and call On Star to have them open if for you.
So there are advantages to On Star Vs a cell phone.
I have never locked myself out of a truck with a fob; it ensures that the key is in my hand when I lock it. Door buzzers are a different story; I am in, out, and around the truck so much that they are simply an annoyance and I instinctively pull and drop the keys before getting out. The last time I locked myself out I had about 1/2 hour to get where I was supposed to meet my boss; I walked down to the hardware store and said "What do you have for burglar tools?"
I bought a felling wedge and 4 foot piece of steel rod; it took about 10 minutes to get back into the truck. (I have AAA but didn't want to wait around for them.)