‘Borrowed Interest’ is a term from the advertising world wherein something in an advertisement which really has nothing at all to do with the product is added to make the product look more interesting. The same thing can hold true in illustration. If you have a kind of dry article you can make something funny out of your visual by adding a twist to the illustration through implementing something that inherently has nothing whatsoever to do with the story. This drawing for instance was for an article about how automated building track the human traffic inside themselves, Does Satan have anything to do with that tech? Heck no, but if I get people to laugh they are far more likely to read on.