Hi,
At the moment, it is used for documentation purposes in Bloc. It is part of the effort of Alex to document Bloc thoroughly. I think it is an interesting idea, in that we would have a significant case study for that can be used later as optional types information to improve static tool support. And it does not hurt at the moment.
Experimenting optional types is a good idea. We could have Tools to dynamically check them.
What about a separate typing model that could be used to add/remove the types annotations ?
Also, I wonder if Bloc is the good package to experiment optional types. Maybe it is not stable enough.
Cheers
Alain