Planning as as means predicting how your future will go it hopeless. Imagine making a 10-year plan back in 2015....
However, planning as a means of understanding the present--especially if you model all of the counterfactual, "iffy" aspects--is invaluable.
Yup, well said. I think the best planners view it in this lens - as a tool, where room is left for the unknown and there is less of an expectation of "sticking to rigid plan" and more "here's our best guess, it's a living plan and we will adjust and refactor as situation changes"