Good question! And I have to first say that I haven't used light table a lot. But from my experience Light Table has what I will call REPL based interactivity. You choose which sections of code to have compiled and then evaluated in the browser environment.

This is different from the the experience of just saving a file and having the behavior change. But you can probably integrate this workflow into Light Table quite easily. Well actually you can use figwheel inside Light Table and have both repl based and file based interactivity. Pretty cool.

I also think that the Light Table interactivity for javascript is not REPL based but I would call file based. But the dominant javascript programming paradigm in javascript is imperative and thus very brittle when working with live coding.