When I first tried the "Save as HTML", I realised that virtually all of the output was to do with reproducing the formatting which would be seen on a piece of paper.
This is hardly ever what you would like on a website. It takes no heed of the width of the window, for a start.
It's also virtually unmaintainable, because the real stuff is obfuscated by all that formatting.
It is the old story - if you want to get there, I wouldn't start from here.