Same for some methods I've since forgotten for solving polynomials. They were non-iterative algorithms that could work with any constants. They weren't faster than other methods, but you could fall back on them when you didn't have anything better.
That is what they were trying to teach me. General solutions that could work with anything. While, of course, it's valuable to be able to intuit shortcuts on the fly, if that's all you're capable of, there's a class of problems you simply can not solve. If they don't click in your head enough for you to come up with a specific shortcut, you wouldn't have a general one to fall back on.
I've always used computers, and didn't understand why my teacher got so upset when I programmed equations into my calculator. Like you'd think writing a program around a family of equations would develop experience with those equations, and I thought it was a good way to speed up the solving process. Needless to say, teacher did not agree, and quickly learned to ban my calculator on tests.
(technically, it was supposed to be banned anyway because it had a CAS... but I got it because 68k TI-BASIC was better than the Z80 TI-BASIC)
I still don't know the general solutions for most of the problems I work with nowadays, and I think that sucks. I think AI makes this way worse on a scale much greater than mathematics.
Sometimes I wish I could go back to school and catch up on all the basics I've been cheating around. I feel like my apparent intelligence is a mistake and I need to develop a better foundation.