There's one in my MY18 and I've put a GiffGaff SIM in it. It gives me extra stuff with the satnav, among other things. Whether that would float your boat is up to you. simpleR and I are wondering if it provides the mechanism for SOTA updates, but the jury is out on that one at present.
Basically, if you want any non-Jaguar provided internet access in the car, the user SIM provides it.