Maybe their cars updates are only allowed to go to .toyota domain names? That’d make it easier to not have your domain name expire on some URL your car is hitting and it gets taken over by squatters or something. At least that’s what I’d do.
Ah yes, why worry about forgetting to renew a $10 domain name when you can forget to renew a $100,000+ top level domain!
Probably works well to prevent phishing or spoofing attempts