Saying it is overrated is like saying sun or air is overrated.
But hyperbole aside, OP also has a point. If we forget that the estimation of probability in itself has a cost, we could be tempted to put more and more resources into more and more sophiticated methods of data collection and analysis to be more and more certain of your estimate. But if we remember that this process has a cost, some times it's more efficient to just add a margin of safety and move on with your life. Bayes theorem is often used for resource allocation, but the process of optimizing resource allocation in itself has a cost.