It is a a WYSIWYG editor, so yes you can use it to update static (or semi-dynamic) pages. But - you HAVE to use some sort of CMS/database system for this to work. In other words, you need a "back-end" where you would access the HTMLEditor to make the update. While you could get around not having a database by saving the content you create to a "flat file," that would be less desirable than simply saving the content in a database and having PHP pull the results.
Here's where you can see it in use on a new site I am developing - the first shot is from the CMS/DataAssaidt update page and the second is a live view of what the public sees (identical to what is in the editor window):
Now, the front end:
Hope that helps,