Sometimes I find the old time letters tiring. I get tired of reading them.
However, they now have become e-mails. Maybe the old letters are long (some are very long for 3 minute dictation at slow speeds) e-mails are shorter. But not always.
These letters you practice writing and taking down in shorthand can help you e-mail efficiency. You will learn what great letters were chosen for that publication and how you can update and change them. Most books (especially the Gregg Shorthand books) have chosen the top letters in business.
And of course the historical or comedy value of these letters are pricess....
"Gregg Shorthand had achieved the most extraordinary success ever attained by any system in the history of shorthand." John Robert Gregg, 1922
Writing emails prior to typing and sending them sometimes is a good idea. Sometimes it's good when you are made or aren't sure of what you want to write. Perhaps write bullet points in shorthand on a steno pad and then you can type them up in the email easily.