Harpie cyber slash good in only 1 deck and it's a UR. They same to almost everyUR archtype related card.
Now, lets check UR of the same box, half of them good in no deck at all.
Konami cannot predict what deck gets popular, they only rate it for the effects.
They start with unique effects like sending 1 monster to GY. If OK, proceed to sending 1 card.
Aloof Lupine is also developed after Foolish Burial in TCG.