All your opponent has to do to avoid taking any damage is cast one spell per turn, and even if they dont, a little bit of damage is hardly worth a whole card
I can imagine quite a few black decks wanting a card like this and its even a demon to boot, giving it some nice tribal interactions that some decks will be able to make use of
After all, they only have 40 HP and must survive till the next turn if they're to become a Pokmon
Virtue of Knowledge Listed at: $10 In Commander, Virtue of Knowledges enchantment side provides redundancy for Panharmonicon decks (and it's better, albeit more expensive: it works for any permanent entering the battlefield)
After all, its always fun to see a creature type expand and evolve
These are staples in most formats theyre in