@millie210 perhaps they want the kids to take the Regents so they can report high scores?
I’m assuming schools have to offer enough Regent courses so that students can get the diplomas. I don’t know if they offer Chemistry if they have to offer Regents Chemistry and make students take the exam. (Assuming they had another course of the physical science requirement.) I never paid too much attention to all the rules, They were being changed while my kids were in school - I don’t think they were the same for both kids.
While all public schools now have to have the Regents, back when my kids first started high school there were high schools that had petitioned not to have them because their courses were superior and their assessments were better.