There are two distinct classes of work that are called "busy work". The first is heinous, the second is often loathed, but great.

There's real busywork: work assigned just to take your time, create something to grade. That's crap, it should go away. (And in my collegiate experience, largely has.)

Then there's "impractical stuff": people often malign work they do that doesn't directly apply to the real world, but I think that it is often worthwhile. Consider MIT's famed 6.001: few of its students ever use Scheme, or any functional language, professionally, but the work in Scheme is never the less worthwhile. (Disclosure, I love functional languages.)