Name another game where the WATER element is famous for BURNING. Go on, I dare you.
Sure, OU players don't have it that bad since Azumarill and Gyarados are physical, Rotom-W only gets Hydro Pump and Greninja is banned, but in UU... hoo boy. The tier is dominated by legions of bulky Waters that aren't quite good enough for prime time, such as Empoleon, Suicune, Blastoise, Tentacruel, Vaporeon, Milotic and Kingdra, and they just love running Scald every chance they get. I'd say Scald is second to only Knock Off as a move you can use whenever you have no idea what your opponent will do... the risk/reward ratio is extremely low. So much so that some people legitimately wanted Scald banned from UU, and Smogon's higher-ups had to put their foot down and say that won't happen. They did, however, make a separate UU ladder where Scald was banned. Yeah, we've reached that point.