I think Liz set it up before a Dreamwidth communication fubar. At the time, our styles were REALLY paltry. Just desolate. So most people had imported core1 styles. And when open beta came, we cut off the ability for free accounts to manipulate layers, and, er, misstep. They couldn't edit the layers they had and there weren't many styles to choose from.

So yes, even free users can have one set of layers to play around with!

What I mean by just tweaking is, let's say there's a style and I like it for the most part but just tweak one part of it. Like, let's say I used CSS to make the comments of a post's author stand out (totally possible using the CSS classes available)--sharing that snippet of CSS, but it's not really a new layout so much as a tweak that could be combined with other tweaks.