#3 really depends on how complex your types are. Lots of legacy JS libraries and applications can be quite... esoteric when typed. Then there are the people tha

#3 really depends on how complex your types are. Lots of legacy JS libraries and applications can be quite... esoteric when typed. Then there are the people that love playing with the type system for the sheer joy of it. The net result is that greenfield TS projects often end up simpler and faster but that’s not very useful for someone buried in an old JS project that enthusiastically abuses the dynamicness allowed.