In the UK (and all the other countries I've lived) emergency service radio traffic has been encrypted for a very long time. I was always surprised (even shocked!) when I visited the US and could hear everything the Police were doing.
For example police patrol would request ambulance for a car accident over unencrypted channel, while SWAT team storming house of another streamer would communicate over encrypted channel.
Reasoning to use open channels I read about is transparency to the public and potential benefit of having non-official first responders.
https://www.zipscanners.com/resources/police-scanner-encrypt...