I'm generally underwhelmed with the whole idea of optional typing in general, because it seems like a solution to the problem of sucky static type systems. The solution is, static type systems that don't suck. If you have that, optional typing seems a lot less interesting.
Programming in 2015 seems to be in this really weirdly reactionary mode to the problems of the 1990s in so many places. ("Event-based programming" as an escape from 1990s-styles threading is another one.) Umm, well, it's great that we learn from the 1990s as much as we learn from any other decade, but I'm not convinced optional typing solves the problems of 2015.
Programming in 2015 seems to be in this really weirdly reactionary mode to the problems of the 1990s in so many places. ("Event-based programming" as an escape from 1990s-styles threading is another one.) Umm, well, it's great that we learn from the 1990s as much as we learn from any other decade, but I'm not convinced optional typing solves the problems of 2015.