Cliffys are a no-brainer for:
Pins with scoops near the flippers (Tron, TZ, CSI)
Pins with no clearcoat (e.g. system 11s)
Pins with guns (e.g. Dirty Harry, where you actually "shoot" a hole!)
Pins with previous wear
Sure, it would be nice to "fix the wear properly", but how many of us can really do this?
I agree with fixing other root causes, like magnets and DTs that are too low.