It's not as though games without attacks are any less luck based. Your carefully built engine can come up entirely in the wrong order near the end of the game where it's most important to close it out. You can constantly draw $7 with your money deck, or even draw a hand of all victory cards late game, losing a full turn. King's Court/Bridge leads to incredibly swingy games where whoever gets KC/KC/Bridges off first just flat out wins.
Also, there's a problem with selecting against high gain% cards. You can't just keep them out of the pool, so there will probably be at least 1 on the table. Since the other cards will generally be of lower power level, the high gain% card is even more likely to take over the game.
This kind of "here's a Witch, in your face!" conflict feels just very ameri to me.