How detrimental are business people using engineering terms incorrectly?

Probably about as detrimental as engineering people using business terms incorrectly, or not understanding goals and priorities outside of a narrow technical domain.

People use words incorrectly all the time, or ask questions that seem to want a quantitative answer when none exists. Doesn’t seem like a big deal.

It depends if it trickles down to engineers having to then build The Wrong Thing (tm).

In some domains, it's difficult or impossible for engineers to get enough information about the actual problems they're solving, in these cases, it's somewhat more important that the customer is asking for the right thing.