@meandavejustice's example is pretty good, but not exactly the best, in that the element already has an `icon-close` class that we can reference which is also indicative of what we're going to do with it. I think the main use case is more where we need to get an element or elements in JS that don't have a class or id at all, or maybe the class isn't very meaningful (e.g. we want to apply a toggle on off behavior to an element with a `.pull-right` class or something...) and we want to make it easily/meaningfully grabbable.

Another arguable use case might be for JS-specific state, e.g. `js-is-active` or something, but `data-` attributes should be sufficient for things like this. It should be noted that grabbing a bunch of elements via `data-` attributes is slightly slower than via class name, though I would imagine it's an edge case where it'd cause a notable difference in performance.

I'll add an example to the doc...