Uses are always much broader than functions, and usually far less contentious. The word function carries overtones of purpose andpropriety, of concern with why something was developed rather than with how it has actually been found useful. The function of automobiles is to transport people and objects, but they are used for a variety of other purposes--as homes, offices, bedrooms, henhouses, jetties, breakwaters, even offensive weapons.
Frank Smith (2014). “To Think: In Language, Learning and Education”, p.108, Routledge