I honestly don't understand why any game is even checking if secure boot is enabled.
If anything it's for the OS to care about that, not individual programs. Afaik, secure boot doesn't (on it's own) prevent the running of arbitrary software, so how is it actually preventing cheating?
It does mean that a signed OS image is running, so demonstrates that the kernel was unaltered at start-up.
It also demonstrates further levels of driver signing robustness.