Plain HTML isn't very workable for a blog. You'd have to maintain:

- RSS/Atom

- the post list

- next / previous links

by hand (and remember to fix the link tests if you change some post title)

And if you want to change the page structure layout a bit, you'll have to update all the posts by hand as well.

You could do without all this but that means it's difficult for readers to follow what's your writing.