Remember when you were in school and your teacher told you what to write about? Those were the go
Beginning
Keyword research is the best antidote for writers block because beginning is the hardest part of writing. If you don't know where to begin, then you have endless possibilities. Endless possibilities lead to never starting anything. In Walden Pond, Henry David Thoreau asks his visitor if he ever wished to write his thoughts. The gentleman replied, no, he could not, he could not tell what to put first, it would kill him, and then there was spelling to be attended to at the same time!
Many SEO's will take keyword research and turn it into a site map for their clients. In these cases, I have the subject for each page I have to write. No anxiety, no lost sleep, no uncertainty " it's brilliant!
Brainstorming
Keyword research, in all it's glory doesn't get you out of brainstorming. Each of the keyword terms recommended by an SEO has many different articles/pages that can potentially be written. Keyword research does give writers a place to begin and a focus.
Uncertainty
Keyword research also combats the issue of uncertainty. As writers, we are constantly concerned with whether or not our audience will like what we are writing about. This uncertainty causes writers to over think everything and never complete anything. Jane Addams said, Our doubts are traitors and make us lose the good we often might win, by fearing to attempt. Keyword research gives writers the confidence of writing what people are searching for.