How I Use It
I think this is a great way to introduce HTML and CSS to students who are new to those languages. It needs some introduction and can get a bit frustrating for some students, so I like the idea of them working in small groups.
I think either having them work in small groups first or on remixes individually is the best way to start. After students have some experience they can work on new projects from scratch on their own. I like that students can easily share their work when done.