To be honest, I think this website is more about the intellectual challenge of constructing the layered dictionary than about actually providing a learning resource. But that is again because I don't see the point of using this for learning. I'd be interested in someone's concrete thoughts about how/why to use this.

To take an example from elsewhere in this thread, if I encounter the word "gauche" in a French text, I could just look it up in a normal dictionary, or I could look it up in a French multi-layered one and invest some effort into deciphering a French paragraph saying the equivalent of "X is on this side of your body: Most people do not write using the hand they have on this side of their body. They write using their other hand."

Sure you can learn such basic terms this way. But why would it be better?