These aren’t for college students, they are for prospective students. Colleges choose weird prompts like this for a couple of reasons. 1) It means that students can’t just reuse old essays from other institutions. (Or awkwardly change small parts of an essay to vaguely fit the requirements of a different prompt, which isn’t really good for the school or the student.)
2) For the most part with these essays it doesn’t really matter what is written, as long as it is written well. I remember the standard essay prompts as being things like “name a time that you overcame an obstacle,” which are annoying to write about and formulaic AF (especially when you are a suburban white girl who realllllllly doesn’t have much to complain about). But really, who cares whether the essay is about overcoming an obstacle or laughing really hard as long as the student shows her ability to think critically and write interesting and grammatical sentences? The college still takes into account grades, teacher recommendations, and (sometimes) test scores, so it is not as though laughing hard is the only basis for admission.