Thanks for the interesting sounding talk link. It's "Types are like the Weather, Type Systems are like Weathermen - Matthias Felleisen" from ClojureTV, for those who rarely click on youtube links. Mathias Felleisen a well known Racket guy, author of How to Design Programs, etc.

Perhaps it helps more in certain specific languages or contexts.

The studies found no general “overall cost” improvement; in other words, the extra correctness came at the cost of tons more boilerplate and “fighting the type system”