Question

True or false: because jargon can be confusing, it should never be used in business writing.

Answer 1

I believe this statement is false.
Jargon includes both slang, as well as technical terms. So if you are writing about a specific subject, you are more likely to use technical terms which are related to that subject you are talking about. So there are times when jargon can be used extensively, and when it should be avoided.