For Police ops, you may be operating at night, in foul weather, hot and high, often over built up areas. You probably want to carry FLIR, Nitesun, loudspeakers, and perhaps a winch or fast rope system. You might want to be able to evacuate a casualty, or transport a police dog and handler.
Do you want a PPL doing that?
Are the more go-ahead air support units wrong in opting mainly for turbine twins?
Yes an R-22 or an R-44 is cheap but can it do the job, and can it do the job adequately and safely?