This is true of both writing and public speaking. I say that writing helps me be a better public speaker; Rasheed Hooda says that Toastmasters and public speaking have helped him to be a better writer. The whole of human history — well, notice it has the word “story” in it! So much of it was passed down through storytelling, before there were systems of writing to memorialize the stories. And Aesop and Hillaire Belloc knew: no child likes to be told what to do, but tell a good story with a clear moral, and the lesson sticks.
I don’t know why business communications should be any different; we’re dealing with human nature and psychology. One of the best cautionary tales I ever heard has stuck with me for decades: a certain airline, back in the early days of air travel — when most travelers were businessmen — got the brilliant idea to run an ad campaign that involved sending these travelers a sort of “buy one, get one free” deal, with the letter: “Next time, bring your wife!”
All was well, until they sent the “thank you for flying with us” letters —you guessed it — to the wives.