I have one of those Cozy Coop heaters for one of my smaller coops. I hung it on the wall, and I can't touch it when it's set on the high setting. I've also had it somehow turn off by itself a couple of times. I have no idea why it does that, but that wouldn't be good if I was using it for baby chicks.
I do, however, use the Mama Heating Pad system. I recommend it highly. It's soft and it's light weight, unlike the Cozy coop heater, and it doesn't get as hot.
The thing that makes the heating pad so successful is that the chicks can press their backs against the heating pad during the first week or two, just as they would under a broody hen. It heats their bodies efficiently in a way that a hard flat surface couldn't do as well.
If, for some reason the Cozy Coop heater fell down off whatever you have supporting it, it could crush the chicks and burn them to death. I do not believe it's safe to use as a brooder plate.