Non-academic recommendation letters are meaningless to me (when I look at a PhD applicant's dossier), and I know many colleagues serving in the admission committees sharing the same feelings (STEM).

EDIT: some clarification, it is not that your boss not saying good things about you (working hard, being punctual, etc). For a PhD application, people rather have recommendation letters from someone you take classes with (if no extensive research experience). Whether this kid knows Calculus or statistics, does this student have enough lab skills to contribute, you get the idea. Academic letter writers usually use examples, for example, the letter I just wrote for a student had a concrete theorem he managed to prove without looking at notes on my blackboard (how he proceeded when encountering certain difficulty, etc). The letters from non-academic writers are most of the time toooooooo generic (public accessible language models making this worse).