Yes, thinking is more important than typing, but after you've had a thought, you need to see it "in writing" and execute it to evaluate it and see if it was a good thought after all.
Fast typists can go through many more iterations of that process in the same amount of time.
It has often been remarked by writers that writing is thinking. That you don't even know what you think until you write it. There is something very fundamental to the thought process that comes from actually recording the thoughts and seeing them "in print".
A good typist (which I'll call 100 WPM, a point beyond which I diminishing returns make further improvement less important) can do the writing-is-thinking process 4x more in the same amount of clock time as a 25 WPM typist.