It's nice but not essential. I am more concerned with the students' lack to master the content before the form. In our society we rarely write in cursive and most people adopt some hybrid form between cursive and print anyways.
There are a lot of things that are nice, but they can't be all mandatory. I would expect the curriculum in our modern day society to be different than the one in past generations. The world is different and we need different skills than our parents and grandparents, so naturally the educational tools may be different.
Well it does make sense if the fonts are not monospaced. In reality I use a typesetting system (LaTeX), so it really doesn't matter what I do :)
I still use double space at the end of a sentence just because I write in emacs and typesetting it on the fly while writing is just too much. But I can imagine that with better computers someday emacs can start doing it, although the constant jitter would likely be quite distracting.