Unencrypted DNS can be redirected or inspected and selectively blocked. DoH cannot, and whereas you can selectively tamper with DNS requests to remove advertisers, devices may fail to work at all if you block their DoH provider.

On a properly-configured network, all DNS requests are intercepted and routed to the desired DNS server. I do this to make Google devices respect my DNS preferences (send DNS through PiHole) instead of using their hardcoded setting.