Not everyone wants to buy secondhand. I know people who have been bitten before and only buy new now. I don't know how true their story is, but often something secondhand is not like new, and if you are picky, you might not like secondhand.

Also, for a school situation, having everyone use the same laptop and software will make this more uniform and easier for the teacher.

I'm not one for elegance but I personally hate having things dangling off my laptop.