I think we are in agreement that rational decision-making is usually valuable, and that some people sometimes cite rationality in order to give false weight to their opinions. To continue your analogy, I'm saying that studying the rules of the road ceases to be a good use of time for most people once a basic driver's license is earned, even if it can slightly reduce accident risk. The possibility of upvotes while having this discussion is making me reconsider.

The universe could be fundamentally unknowable, though this possibility doesn't seem very useful.