I don’t think the “Why X” essay has to be gimmicky. My kids talked about profs they had met on campus tours or classes they had attended, specific classes that looked interesting in the course catalog, research facilities associated with the school, and ECs/clubs/activities they wanted to try out. One of my kids wanted a school with high rigor after attending a very rigorous summer program for a couple of summers – for schools with that particular reputation, she talked about that as a fit element.
For this particular essay, your goal isn’t really to be totally unique. The main reasons they ask the question are (1) to judge fit – do you understand the school? And (2) to see if you really researched the school, or if you are just tossing in an app and don’t know much about them. They are concerned about yield – a student who has a solid answer to the “Why X?” is more likely to decide tonstrend if accepted. A direct, sincere essay works fine in this case.