The biggest benefit is for riot and civil disturbances. For those getting bricks and bullets sent their way, they are very good for patrol folks. Some activities are also good to use. I spent a lot of years wearing a helmet while working our crime suppression bicycle team, and then in Air Support. Critical safety equipment in both. Very rarely did I ever need one in patrol, so again weigh the options.
If it is a matter of the agency blowing $400 for stuffed animals in the trunks to hand out or a walking path for the office people versus ballistic helmets for the troops.......ballistic helmets. If it is the difference in maybe rifle plate carriers and plates versus helmets.....plates.