My own son pulled a Zekrom in a booster pack, all shining foil, and he was confused about why you would use an attack that damages yourself until he noticed that, wait a second, dad does that mean yes, that is what it means! Yessss. It won't be hard for you to tell what is advantageous about it, particularly since every ten points of damage is a distinct "counter" in game terms. But the idea of trading temporary disadvantage for long-term advantage isn't entirely inbuilt. The ratio of hand-birds to bush-birds, and when you should choose between them, is something you have to learn. It might even have been your father who taught you.