ASCII text shouldn't be accepted because:
Pen and paper is by far the most portable format on
the planet and beyond.
Not so in this context. Anyone interested in the Internet has access to the
Internet, and for anyone with access to the Internet, ASCII text is more
portable than printed paper. Therefore ASCII text is the most portable
format for this application, even more portable than paper.
For example, there are more people on this planet that
have access to a pen and paper than a computer.
Those who don't have a computer aren't going to care about Internet drafts.
Heck, my grandmother refuses to buy a computer even
though she can afford it, but she can sure write a
mean letter.
Does she read a lot of Internet drafts?