I will admit that, it's a great way to get all together for fun, but has little value in the social salsa scene .
This is all done via the rueda structure! In some ways, I use the rueda to bait and switch. Make them feel like they're learning moves but then end up teaching the structure that underpins casino and how to create flow in the dance. I also make them freestyle dance based on the moves they learn at the end of the class.
In fact, it's very effective. At first, you show some movements and memorize, then you visually reinforce it. The strength of rueda is that you can do and watch at the same time. In a rueda it's also quite obvious when someone is off, leading people to pay attention to timing, and the flow of the moves. So if you're not a "move based" teacher, the rueda can actually a powerful tool for technique training. The problem is that rueda usually attracts lazy, move-focused teachers. Then again, who isn't a move-focused teacher these days? It seems 90% of teachers just take the easy way out - they entertain students rather than focus on teaching. My personal feeling on this phenomenon is that it has little to do with rueda and everything to do with the person teaching.