I personally bounce back and forth about this. My experience is probably colored by the fact that I'm doing this in C++. Boilerplate gets annoying there (and attempts to cut it down tend to produce lots of incomprehensible function templates). I like the idea of using types to encode assertions at a fine granularity. I dislike the amount of tiny little functions this creates. I also dislike that the resulting code is only navigable with an IDE - otherwise you spend 50% of your time chasing definitions of these little types.