This was an exam question for my course and I am struggling to actually answer it in a way that is not fluff.
Here is my current answer:
CFGs describe how non-terminal symbols are converted into terminal symbols via a parser. However, a scanner defines what those terminal symbols convert to in terms of lexical tokens. CFGs are grammatical descriptions of a language instead of simply defining what tokens should be scanned from an input string.
What is the correct way to answer this?