An improvement on Rapidash (FRLG)'s Fiery Aura that had to be active, Volcaronais good as a bench sitter, as koolkidhp, because its Scorching Scales are usable from the bench. No, it doesn't stack and it is unfortunately not too much better.
The problem with Burn is that you do not know if it will hit or miss and the opponent can attack through it without hinderance. Burn is better as condition that works in combination with the other conditions (Poison and any of the ones that force a turn of the active).
Obviously, it is best used with a Pokemon that can auto-burn. 110HP takes it out of sniping range of most pokemon, so it will have to be Catchered. That means the opponent needs a Switch-Catcher combo to get rid of the Burn or attack anyway despite the Burn. As a stage 1, it wouldn't be too hard to set up 2 at the same time.
If you have a deck that can block retreat would also be suitable. Perhaps Houndoom Prime? It too is a stage 1 so easy to set up. Flip for burn from the active and bench with its Power, and then trap the pokemon active while burned with your attack. Dark Patch will help the deck accelerate energy. If you end up attacking with Volcarona, discard :dark: so you can Dark Patch it later. Perhaps it could see fun play at a battle road or league tournament.
I'm still not entirely sure what a Volcarona is. It looks like a stink bug, which gets it my thumbs down.