I believe the point of Omega is to make it easier to set up hypothetical situations without getting fixated to much on irrelevant details.

The issue is that often those irrelevant details are generally the crux of the problem.

The Newcomb problem is a great example: someone trustworthy presents you with two buttons. "If you press the left button, you get $1,000. If you don't press the left button and you press the right button, you get $1,000,000. If you press neither button, you get nothing." The right response is to press only the right button. Why would anyone care about this question?

The change from my summary to the real thing is that the person is made infinitely trustworthy but makes a statement which is also infinitely unbelievable. See, rationalists sure are dumb because they don't take anything on faith!