What you are saying about it costing some fee for communication makes sense.
I have a question for you, I know about cars but not so much about wireless communication.
Do these cars have a modem type of device in them? Can they be used as hotspots for jumping on the internet? I apologize ahead of time if these are foolish questions. I don't understand how they communicate wirelessly with smartphones etc.
Yes, they have some sort of 4G/LTE cellular modem, although I don't know which carrier they use. Most likely AT&T, T-Mobile, or Verizon. But no, they don't offer a hotspot, as others do. The hardware to offer a WiFI hotspot probably isn't contained in the cellular modem, but maybe they do and it's something that Kia could enable (for a fee, of course). My daughter's Pacifica PHEV has a hotspot that works great for the kids to use their iPads while driving, assuming they aren't watching something on the built-in screens. I believe they pay $10 per month for some amount of data (I don't know how much), but I don't think they've ever exceeded the monthly limit.
Using the cellular connection in the car, it connects to servers maintained by Kia (or a 3rd party that Kia pays), and those servers maintain the logs for each car. With the app on our cell phone, we connect to those same servers and retrieve our specific car's data. So the app doesn't talk directly to the car. It goes through the servers, which relay the information between the two. Same with any commands we send via the app (unlock doors, reheat/cool the interior).