I can't think of an instance where my 20-30 wpm typing held me back in a messenger chat - if anything, my typing speed in enough to present the other person with a wall of text, something to be avoided if you want to have a dialogue with someone.

And yeah, someone who speaks in full paragraph or essays is unusual. The average transcription of an extemporaneous speech shows a lot of "uh's", backtracking and so-forth.