Another thing to consider about such editors is that they can actually add complexity to building a web page just as easily as they can take it away.
Using a visual editor means you're actually dealing with two sets of rules instead of one. You not only have to conform to the rules of HTML, but also to the additional rules of your editor and how it wants you to do things. To a beginner that probably doesn't fully understand the rules of HTML, let alone those of the editor, this can be a rather counter-productive situation.
I've seen it happen to a lot of people recently. They don't get properly exposed to the actual HTML and so never gain a decent degree of familiarity with it, and when they have problems it's difficult for them to figure out whether they're breaking the rules of HTML, or the editor.