Why do I have to do this electronically?

If you absolutely insist on doing all this work by hand with paper, you may be missing out on an opportunity to save hundreds, or even thousands, of dollars in fees and postage.

Where the true speed and efficiency comes in is with presorted mass mailings.  You can literally save as much as half of your shipping cost if you automate things the way the Post Office likes it.

By the way, the Post Office itself is moving to a much more automated, streamlined and electronic way of life.  You don't want to be left behind.