a teacher's job is to teach their students. a "banker" (at the sort of bank where you might open a checking account) isn't expected to grow your checking accoun

a teacher's job is to teach their students. a "banker" (at the sort of bank where you might open a checking account) isn't expected to grow your checking account for you. you're supposed to do that, and the bank is supposed to hold it safely. I don't understand the comparison you are trying to make.