Unfortunately, in some cases it is not clear what exactly you should calculate to make a good prediction. Penrose interpretation and MWI can be used to decide—at least sometimes. Nobody has (yet) reached the scale where the difference would be easily testable, though.
Yes, doing the calculation and getting the right result is worth of many interpretations, if not.all of them together.
Besides, interpretations usually give you more than the truth. What is awkward.
Unfortunately, in some cases it is not clear what exactly you should calculate to make a good prediction. Penrose interpretation and MWI can be used to decide—at least sometimes. Nobody has (yet) reached the scale where the difference would be easily testable, though.