It can write a chess engine because it has read the code of a thousand of chess engines. This benchmark measures a different aspect of intelligence.

And as a poker player, I can say that this game is much more challenging for computers than chess, writing a program that can play poker really well and efficiently is an unsolved problem.

The program doesn't need to be a solver. It can be anything that helps it.

It doesn't even need to be one tool but a series of tools.