Working uncertainty into time estimates still just gives you two sets of times to consider, with no way of knowing why you missed the low one and just if you will hit the high one. (Unless you do really wide bars on your estimates, in which case, the high bar is going to be worthless.)
That is, if you give me a high confidence and a low confidence estimate, how do I know why you missed it when the time passes? More, how "close" to making it were you? If you got half of the work you estimated done by that time, I'd know you were about halfway there. If the date just passed, all I know is that you didn't make it.
And I used "I" up there. But it is really even more personal. All you know is that you didn't make it. You literally don't have anything to learn there.
Contrasted with any work you do. Look back and quantify what you did. Not how long it took to do it.