They are trying to assess overall fit and the likelihood that you would pick their school if you were admitted elsewhere.
For example, if all of the other schools you applied to are 3X the size of their school, they’ll wonder whether you secretly want a larger school environment.
If there is no pattern to your list of schools other than similar “prestige” or notoriety, they might wonder whether you’ve done your homework to understand their school or are just applying to some magazine’s random “Top 10” list. They might suspect you’ll choose a school based on ranking, not fit.