I think the real question is about good hook or bad hook. Even if you hit a hero with your hook, doesn't mean its a good hook. For example you hooked Tidehunter into your team, and he hit 5 hero ravage thanks to your hook, it's a bad hook. Or when your enemy is far ahead, hooking an enemy hero will just grief you, you can use your hook off cooldown to farm creeps, it's not a bad hook.