You will find that they operate on local law enforcement frequencies more than their own repeaters, which are still DTMF. If nearly every person I made contact with carried a loaded gun, I would prefer to have radio interoperability with the other officers around me if things get hairy. Plus, in most rural counties, you can count on no more than 10 officers working at once, including deputies, constables, troopers, and small police departments. They won't be over-burdening the dispatch centers with traffic.