For me, a big benefit is the tooling support. If the API is statically typed, I can easily find the headers I am able to set using my IDE. And for setting the date I don't have to check the http spec for which syntax I have to use for the date.
That's not a bad point, I'm just not sure I am willing to give up functionality for tooling. The end goal here is a program that people can use to get things done, not awesome IDE integration.
