can't help but think that it's easier/quicker just to have the book open, so that the students can see the help
My Godson attends Boston University (BU) and even the dorms are wired for DSL! My son has DSL and can have several pages up simultaneously so the situation Jackie mentions may not be an issue.
That said, there is something about books - I think it would be hard to manage a computer while snuggled up in bed - books are easier to adjust.