Isn't the point that if pure Python was faster they wouldn't need to be written in other [compiled] languages? Having dealt with Cython it's not bad, but if I could write more of my code in native Python my development experience would be a lot simpler.
Granted we're still very far from that and probably won't ever reach it, but there definitely seems to be a lot of progress.
Since Nim compiles to C, a middle step worth being aware of is Nim + nimporter which isn't anywhere near "just python" but is (maybe?) closer than "compile a C binary and call it from python".
Or maybe it's just syntactic sugar around that. But sugar can be nice.
So python programs, that already spend most of its cpu time running these libraries code, won't see much of an impact.