Page numbers
Some professors have moved with the times and do actually ask for a word count when they set an assignment, probably because most papers are done on a computer these days, which can make calculating the word count easier.
Quite a few teachers do still ask for a one or 10-page paper to be handed in on whatever subject they’ve been talking about. This Twitter user is right, it is a bit odd, as it means those with larger handwriting have to write less, and you could use paper with wider spaced lines if you wanted to.