I'd forgotten there even was such a thing!
The URL you referenced seems to have a good explanation. If you are coding EL and you need the EL to reference a "throwaway" bean that exists only for the duration that that particular EL expression is being evaluated, NoneScoped would be suitable. Not that I've ever needed to do that, but it would allow you to offload complex computations and other data manipulations into
Java code instead of doing them in EL - which is both potentially an MVC violation and definitely a

to debug,
From that usage, I think I could consider them as a UI equivalent to Session EJBs, only something between stateless and stateful; stateful EJBs would retain scope between uses, whereas the NoneScoped beans would simply be discarded.