Is computing Chaitin's omega the most pointless waste of time that can possibly be imagined, by definition? If you actually had the value can you do anything with it at all?
As noted above: you could solve the Halting Problem, and compute optimal data compression. Oh, and then we could go ahead and calculate Kolmogorov complexity K(x) for any arbitrary string, thus allowing Solomonoff Induction and AIXI to work. If you can compute Omega exactly you can thereby do almost anything at all.