WYSIWYG editors aren't perfect and will sometimes produce non-valid HTML/XHTML. its also very difficult to make a very specific change to the structure or styl

WYSIWYG editors aren't perfect and will sometimes produce non-valid HTML/XHTML. its also very difficult to make a very specific change to the structure or style. in only using a WYSIWYG editor, you're ceding control to the editor. your page looks like what it wants it to look like. if you want something more refined or exacting, you have to hand code.