Do they have a book buyback program? Do they even have these anymore? If so, I wonder if they could get paid in Bitcoin?
Buyback does exist. It all depends on how the store runs it.
College bookstores tend to not hire much IT, so they often heavily rely on packaged solutions from vendors that roll the entire program into one system. Managing the supply and demand for a book, determining how much a book is worth at a given moment, and where that bookstore should send it to be resold (since not all buyback books go back on the shelf at the same school). This is a lot easier for stores to manage if they don't have to deal with those logistics.
In some schools, the money is handled by the actual store, so they pay you out of their own account, then bill the buyback vendor for those books. (Minus the ones that they keep for themselves)
In other stores, it's the other way around, where you're given the vendor's money, and the bookstore ships away what it doesn't want and pays the vendor back for what it does. (This is easier for accounting because the store doesn't have this new type of transaction that's always a refund, them gets offset a month later. They just buy what they keep as if they bought it from any other publisher, and ship away the rest without having to deal with it because it never goes through the regular till or inventory).
So if a store is implementing the second system, they're really at the mercy of what the vendor will offer for refunds. And with the first system, volatility is an issue as always, since the store might not get the dollars back for those books for a few weeks.
When I was in college, the bookstore would only buy back books that would actually be used the following semester (often times a new edition would come out with essentially no changes except for the edition number). If the book was no longer the "latest and the greatest" then they would offer nothing for it (I never heard anything about giving it back to the
vendor publisher).
To answer your specific question: the bookstore likely uses either bitpay or coinbase to process the bitcoin payments, converting the payment to fiat right away. I would personally doubt that the bookstore would bother with giving bitcoin for used books.
With that being said, most campuses (I am not sure about MIT specifically) have both for profit companies that deal in used books and somewhat of a P2P market for used books. I would think there would be a good chance that users of a potential P2P market would deal in bitcoin and that the for profit companies may give payment in bitcoin for used books
