The priest who did our marriage prep told us that the results are meant to be conversation starters, to help you find out if there is anything you need to communicate about better for the sake of your marriage. We had no surprises with ours, as we had been dating more than six years and new each other and our families pretty well.
Mostly the differences in our answers came from differences in how we interpreted the questions. It was an interesting exercise in learning how we both approach language, at least.
For example, one of the statments in the agree/disagree/unsure questions was something about being bothered by the fiancee’s use of drugs/alcohol. I answered no, because my husband does not abuse drugs and uses alcohol lightly and responsibly. He said “unsure”, because my habits are similar to his, but figured a no would mean “she uses drugs and alcohol and it doesn’t bother me”.
I would call it a worthwhile thing, but it won’t add much if you already have good communication.