Many companies have mission statements, and they're handy to reference in all - hands meetings or a quarterly report, but they're more for rhetorical purposes than anything else. (businessinsider.com)
They often receive explicit instruction in English classes on how to write essays for rhetorical purposes — for example, to explain, describe, or persuade. (ascd.org)
Look, the rhetorical purpose, actually, is maybe interesting as you're the writer. (redeeminggod.com)