I also offered a board to roost on (that's in the shed now too), they still wanted to be on the plate. Also I'm not sure 3-4 chicks can cuddle for warmth as well as a dozen. I'm not saying they're not ready though, maybe offer and old desk lamp with a 60 watt bulb when you have time to check them often? I know how you feel, gotta get them to the next stage but you don't want them to suffer either. I've read different temperatures by weeks, there all close but vary by like 10 degrees. On the other hand remember chickens are raised world wide in all kinds of conditions, including no electricity, with success. They are tougher than you think but those other conditions include a mother hen for warmth (who might kick them out of the nest by now!

).
More energy consumption is part of the equation but I also don't like not being able to check up on all of them because they are hiding under it and in the garage, in the brooder, when it's 15 at night, my temperature lazer was showing pretty low temperatures under there and most of them preferred the lamp. I give them one of the 3 pallet boards in a darker area with a board over that side, they can dark nap over there.
I'm not concerned about a chicken breaking a lamp hung properly. Give them the 18" of head room, don't trust the clamp, watch your clearances and material type and it's going to work safely. Try giving a goat a heat lamp they can reach or chew on the cord, that's going to break and probably light up the building

. Lamp next to wood also bad. The steel and poly tubs are popular for a reason.
I think it depends on where you are, if you don't worry about your pipes and spigots freezing in the winter the plates probably have more value. Also if you can get local birds that don't have the stress of being mailed so you don't have to worry about pasty butt as much and have better genes maybe you don't have to check them as often and it's okay for them to hide. Personally I'll keep the plate as a backup should a bulb burn out or if I don't have power and need to conserve amps to run the generator, that kind of thing.