I saw Melton talk about this for years at conferences. Like most induced differentiation problems it's essentially combinatorial chemistry as applied to cell signaling - a truly staggering number of 96-well titer plates went to incinerators to bring us this result. Not to mention repurposed IVF embryos.
It's a substantial advance. But the problem with the irrational exuberance like that displayed by Olberholzer (as important as the discovery of insulin? Really?) is that this mode of curing the disease - beta cell replacement - has, strictly speaking, been around since 1999; it's called the Edmonton protocol. Recipients are on immunosuppressants for life.
Type I diabetes is an autoimmune disease, and that's the real bear - stopping the re-rejection of the beta cells. The semi-permeable membrane as a protective envelope idea has, likewise, been around for decades. But getting it to work is a hard problem and, really, the central problem vis a vis a cure.
Now, what Melton's results add is a way, potentially, to make cell introduction trivial - after all, if the reagent's plentiful and cheap enough, just do a subcutaneous transplant every month and let the cells be rejected again or the membrane be scarred over, and pop in a new one!
But when you say it out loud like that, the limitations of that approach when actually applied become more apparent - is it really practical to subject patients to something like that? What about intermediate conditions as the effectuality of the module dies down?
In other words - neat, but unanswered questions still abound about how to make this work as a practical cure.
I can imagine subsequent steps to be performed on these cells aimed at reducing their antigenicity by reprogramming. That's more research and more trial and error - maybe 3 years' worth, but that seems awfully optimistic.