I have always believed that passing any test is only truly a measure of the ability to pass that test - extrapolating to other abilities is dangerous. This is also true of these Acid tests. What matters in a web browser is the ability to view the websites you want to view without any problems, not the ability to jump through hoops like this. A browser with a good score is likely to render most sites pretty well, but then so do some with low scores.
FWIW, my copy of FireFox scores 72/100 which is pretty good. My copy of IE6 scores 12/100, yet a very significant portion of the world use this browser every day without real problems.