At the risk of being facetious, one key benefit is that Future is a named concept that lots of people will recognise and understand, for example it has its own wikipedia page.

I don't recognise the ContT type which you say is equivalent. I tried to find it in the scalaz docs, but it is listed there with no explanation. Where can I read more about this, and how do you know it is equivalent to a Future?

You say that "an Applicative instance runs Futures in parallel"; would multiple ContT operations not be run in parallel? That is a key feature of Futures , and might be an answer your question.

UPDATE:

I see now that ContT is an implementation of continuation passing style, and that scalaz.ContT[Trampoline, Unit, ?] is a special case of a continuation passing function that may be isomorphic to Future , if certain external assumptions hold.

I think that the answer to your question is the same reasons that many other special cases are given prominence when they could perhaps be thought of as one case of a more general structure: