yield from was actually the gateway drug that got me to upgrade to Python 3.
A backport like this (perhaps all backports) should come with a warning that says, “If possible, switch to version_N+1 before using this”. Allow me to explain:
This feature makes co-routines palatable in Python2. About 1.5 years ago, like @joelgrus I was stung hard by this missing feature in Python2. I guess I learned the hard way, and every project I have started since then is in Python3 (There is NO reason not to).
My point being, if this library was available back then, I would have used it. And I may not have switched to Python3 yet, and that would have been a sad thing, as I would have been missing out on the other goodies.
I heavily used coroutines in Python 2 via twisteds inlineCallback decorator. It was awesome.