I love it when a copy editor helps us save face. I’ve worked with a couple of really excellent copy editors—ones who showed me how it is possible to address a problem area with the lightest possible hand. They really respect the author’s voice (and I wasn’t always the author). I also appreciate the copy editors who understand the niche.
Any good editor knows their “mantels” from their “mantles,” their “rains” from their “reigns,” and their “role it plays” from their “roll it plays.” But not every editor might know that a “box mean” should be a “box beam,” or that “tare the weight” should not be “take the weight.” And they know when non-standard spelling and grammar are appropriate. It can take a specialist to know that “exergy” is not a typo for “energy,” and that “fertility” isn’t a more familiar word that means “fecundity,” or that “kitteh” is a perfectly acceptable—perhaps even preferred—spelling for the readership.
Learning the jargon and argot of a niche can make an editor extra valuable to an author. Editors can learn that lingo by reading broadly in that niche, attending conferences, taking training in the field, and editing the work itself as long as they remember to look up everything that “seems” wrong, and check their assumptions at the door. In fact, diligent editors look up things they “know for sure,” too. Sometimes they find that “iff” isn’t a typo either.
When an author realizes that the editor knows the niche, they are more ready to accept their editing suggestions. And that matters even more when the editor is suggesting substantive changes; the authors want to know that the resulting structure will be respected and recognized by the readers in their field.