When Maven car share was a thing, I rented a car from them once. It used app with Bluetooth to open/close the doors. The design was horrible. Anytime I’d step away from the car, the phone would become unpaired. Getting it to repair was nontrivial, and the easiest way I found was to reboot my phone. Eventually the car unlocking process became extra ornery & I had to spend something like 10 minutes in the freezing cold weather just trying ti get the car open. I was not pleased & never rented from them again.
When I used to be a ZipCar member, they had a keycard I kept in my wallet. That worked well enough.
