Is cheating worth the penalty? Yes, it appears so if it allows you to secure a championship or two.
Of course, timing your cheating is key - you get more bang for your cheating buck if you do it at the start of a new regulation set because you get a head start. Cheating in years 2, 3 or 4 will give you progressively less bang for your cheating buck because the teams naturally tend to close up over time.
BY doing it during the design/development phase of the new regulations, RBR have stolen a march on their competitors which might be very difficult to overcome.
Having said all of that, I wouldn't cheat. Everyone knows you cheated and everyone has an asterisk next your results even if the official result doesn't. Those of us with longer memories still consider that Schumacher cheated in his attempts to win titles, even if officially he is held up as one of the GOAT candidates.