I've been using them from the off Dai, a lamps too bright without one!
In a lot of places filtered light is a must, because critters are too spooked without colour. Though dont get me wrong, once they know what filtered light is, they are on to it same as white light.
One thing i've never done is run my quarry with the filter still on, though it seems a lot of people do...!
Me an my dog are out there to catch quarry, it aint the Waterloo Cup out there, so i'm gonna give that dog every chance i can and dazzle the feck out of whatever i'm gonna run.