Cope. No matter what deck, even in decks that downright directly benefit from discarding cards as a cost, discarding is still a cost. Check the duel log when this card was activated: it clearly says COST in full yellow below the card discarded as a cost for a card effect that required a discard.
Still cope. Decks that have cards that directly activate when discarded as a cost are a minority, and as for decks that have cards with graveyard effects, that only works if 100% of the deck has a graveyard effect. I beat so many tryhards discarding all their blue eyes without having any follow ups and running out of resources. Bricks will happen, so discarding is a potential issue pretty much alw