The lib is very, very flexible, so you could code a responsive site that worked via non-JS methods, then use it solely for progressive enhancement. It's basically a way to set arbitrary content rules within the content (A relates to B in a certain way when this is true, and in a different way when that is true) and define the interactions, reasonings, and timing in the script.
Completely agreed, and I like it a lot for that use case. I'm just not wild about it basically being pitched as a married-to-the-markup alternative to CSS.
