Choosing any specific field in engineering would result in just about the same use of plain language. It depends on the audience, for instance, a mechanical engineer talking to another mechanical engineer would use highly technical terms. However, a mechanical engineer would use plain language to get across the qualities of a part to investors or the public. Plain language is more important than technical terms because it doesn’t matter how good a term is if people don’t understand what it means.
While highly technical terms matter and are useful to experts in their field, they don’t convey the same meaning to everyone. Plain language will always be needed for just that. It is the same with any profession or career, not just engineering jobs.