If they can't provide service I'll be going to other brands that's have a larger service network.
Shouldn't have to replace it for a long time (if ever) and seems to work fine. More expensive than lead acid but more convenient than service appointment for a 12v battery.
One thing to note though is that not all repairs are mobile serviceable. For example, when my Model 3 needed its front control arm replaced part of that service involves doing an alignment. The Mobile Techs aren't going to be able to do that one.
The app does a pretty poor job of not allowing you to specify issues outside of the standard flow. I could have called a service center but between how hard it was to source a 12v battery independently(I know it's a deep-cycle battery but still!) and high mileage I just don't think it's a car for us any more.