That said, async/await produces stuff that implements std::future::Future. The existing async ecosystem was built around the futures crate. Once std future hits stable in the next release, the Futures crate will release a 0.3 version, which has compatibility stuff between the new futures and futures 0.1, so you can technically bridge between the two worlds.

The benefit is basically "you won't make your users use a bridge between your code and the new stuff".