@Captain Torch
That's mostly true, but you're missing some details, Natsu, Wendy, and Erza with Dragon Slayer abilities hurt dragons, and they were much weaker than them, yes, Durability of the Dragons is far higher than their AP, however with Dragon Slayer Magic, they bypass their scales, the Dragons Durability without scales is very vulnerable, considering opponents like Wendy can damage them, and Erza who was likely High 7-A when falling to attack Irene, One-shot her Dragon Form, it's probably like attacking a humans muscle tissue, since scales are basically a Dragons Skin, so it doesn't make the fight "equal", it gives you a good advantage against someone who would be stronger than you, but that doesn't mean you'll win
It just means you're super effective, like in Pokemon when you have a type advantage, but a strong enough Pokemon can still easily beat a weaker one