Again, Chinese radios are cheaper.
Public safety workers that buy and use these type of radios are doing it because they are affordable. Departments don't always buy a radio for each member. If your a peon and want your own radio, then you must buy your own. My department frowned on our employees buying HAM rigs and modifying them, but we didn't push the issue. Of course, some members bought "real" radios also. We didn't like that either, but turned a blind eye as well.
All of our trucks have 2 official radios. When exiting the vehicle while on a run or errands, both radios had to be taken with you. Personal HT's are used for comms coming to and from work or responding to an "all call" while off duty. I imagine most departments have similar usage. I was also on the local volunteer department and modified HT's are widely used. Most local VFF departments cannot afford 20-30 handhelds. If the Chinese radio craps out, run to the truck and finish your transmission on the official radio.
Our motto was: Improvise, Adapt and Overcome.