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.
My father was a brakeman/switchman, which meant (among other things) that he more or less didn't exist; I had no Shadow Dad to be a proxy for, which had advantages in its own way.
I want to emphasize however that these advantages did not extend to race victory. My own Pinewood Derby car was so objectively bad that I laughed as it lurched down the slope. I was given a Sportsmanship Trophy for it, in fact; either because my laughter was interpreted as laudable equanimity or because it had that edge of madness associated with previous Dark Scout incidents, and they thought a bit of recognition might tamp down the voices. But you couldn't not laugh! It was horrible. My nominal "car" was largely unchanged from its primal state, except for the addition of a single black and white pinstripe on either side. I don't think they were the problem, but I am no expert; I'll look into it.
My son's projects look as though a child made them. He was commanded to make a diorama about Washington State, and he fabricated and (subsequently turned in) a "rocket sled prototype." He's in Kindergarten, who gives a shit. Brenna felt bad, because she had seen - as I had - the projects with the functioning boats, the expert calligraphy in a dozen languages, origami croissants which had never known the touch of a child. She felt sure, and this may even be true, that we would be judged as parents on "his" craftsmanship.
I laughed again, and it was the old crazy laugh from before; this time, no award was forthcoming.
(CW)TB out.