There are two minor problems with that:

1. Most computers are only set up to
recognize .htm and .html as .html pages;
when the user goes to look at his files,
using his browser, he won't see an .shtml
file in the dialog box. It's at least a
bit of aggravation to keep selecting
"show all files," and some users don't
know how to do that - much less change the
file associations, or use a "Find" function.
Thus a certain number of saved files will
be "lost" on computers.

2. .shtml doesn't look all that good.

Any alternatives?