I duel degreed in undergraduate earning a BA and a BS simultaneously. The classes in my BA major used MLA and the classes in my BS major used APA. It seems like it was the same in my gen eds, arts classes tended to use MLA and science classes APA. I liked MLA better, APA wants more concise writing and I tend to be somewhat wordy. In my professional career I mostly deal with spreadsheets and autogenerated reports.

Highschool has very limited specialization. You learn lots of stuff you'll never use because they are trying to give students a wide base of basic knowledge and skills that will be built upon wherever you go next. It is meant to prepare you for a job or a college major but not any specific job or college major. You specialize more in the next step and the further you advance the more specialized you get.