Reviewing past hands is not about the exact cards or situations; it's about analyzing patterns, ranges, and tendencies.
True, it would be useless to study what to do if we drew
in the hole and the flop came
, because analyzing that exact situation, as you inferred, would be futile.
However, it does help us tremendously to look at patterns and ranges, against certain "types" of players.
For example, if we preflop raise to 3BB OTB with
and the BB flats, we can... by looking at past hands... learn a lot about how to play a board pair, for example, against an aggressive blind defender.
We *can* learn about certain ranges and certain calling/betting/raising tendencies, for example a player with a VPI of 39 is much more likely to call every street down than, say, a player with 19/12/1.8.
The most important reason for analyzing our hands is to look for leaks in our play, to see where we could have played a hand better, so that the next time we are more equipped.
This is no different than any other education or skill acquisition, such as learning how to play right tackle for the Bears or how to develop a cure for pneumonia. We learn by looking at the past and seeing what worked and what didn't.
I always review my hands from the previous day during breakfast and since doing so, my game has dramatically picked up.
For the hands which trouble me, I post them and ask for input from others. Having a different perspective on a hand, e.g. how someone else would play it, teaches us objectivity and adaptability, two important ingredients of skilled poker.