Became important when you extend, for example, DefaultValueAccessor to work with ng-model
and see a list of errors:

ERROR in ./rating/rating.ts
(50,5): Supplied parameters do not match any signature of call target. (2346)

ERROR in ./timepicker/timepicker.ts
(151,5): Supplied parameters do not match any signature of call target. (2346)
...

I was trying to do it my self but, but constructor type parameters are come as string, not parsed, to dgeni templates