There is a use for them O:
I'm not an expert on it. But I'm pretty sure what some people do is gut the blade of all it's internals and put blade film in, like ultrasabers blades. I think I've also heard that some people have tried to use the stock internal diffuser, but with bad results on an LED setup.
IMO, there's no use for the internals (led string/diffuser). Maybe for DIY EL builds but even then there are better resources for that. Makososai for one.
So keep the bladestock. Invest in some diffusion film (
http://www.ultrasabers.com/Blade-film-P197.aspx) and hot glue. Use that blade for the saber it originally came (for the sake of fitting in the blade holder) or on any other saber it fits in and you're good.
I'll try to find an example.