instead of holding a flashlight , why don't police officers have them on their uniform?

love it

If the flashlight is on the uniform the officer has to turn his/her body to see in a different direction instead of being able to scan... Also makes an aiming point for a gunman to shoot at instead of having to guess exact place where the officers body is in the dark...

To much weight if small they do have them on the belt

Nowhere near the amount of range or control. Plus, they often use it as a cudgel in case they have to break a window or something.

They can have them on their heads like miners.