Short answer: yes, you're wrong.
Longer, more nuanced answer: It depends on where you are and how comfortable you are being solely reliant on cell service if something goes wrong.
I spent most of last week in areas with at best spotty (but usually no) cell coverage running GMRS radios for car-to-car and hiker-to-hiker comms. Worked great.
FRS radios would work for most of that, but there are places without cell coverage where I can talk through some of our mountain-top repeaters that, were I or someone I was with to get hurt, we could call for help even without cell service. That's an edge case of an edge case, mind, but it's nice to have as a backup.