User blog comment:B214/Volume 22 spoilers/@comment-30289101-20161022000600/@comment-9595671-20161022032216

Actually Kuroka's case comes from a rule. In the tournament, even those who have consumed 2 Evil Pieces will be treated as 1 piece, the exception being Gods who'll also take all 8 pawns. Also due to the fact she has Bishop Evil Pieces, I doubt she was allowed to take a non-bishop role.

So they still do measure strength, the tournament just has a higher standard than normal for those who aren't reincarnated Devils but also strong rules for the Gods to balance things.