Apple doesn’t allow it. Users do , when they agree to share whatever let’s the funny nightmare rectangle play trendy and pleasant sounds from car sound nozzles. While also an automated voice reads texts aloud in the name of hands-free, for all occupants (and some outside if the volume is up). And also it needs to contact info, to make calls for all the silly-fillies that want to use siri while driving. And shoot to reply to meemaw with a family photo siri needs to access your images.
Meanwhile your new infotainment system is sending all this off like a $45,000 copier that it is, sending it off in packets when it gets wifi signals, because the kids needed that for their Xbox on road trips.