I think there's definitely value in this kind of JavaScript-in-JavaScript type of dev utility. The main advantage is cross-browser dev utilities - which brings

I think there's definitely value in this kind of JavaScript-in-JavaScript type of dev utility. The main advantage is cross-browser dev utilities - which brings us closer to a cross-browser dev environment. Browsers have historically opted for hiding runtime management (debugging, etc) behind myriad APIs, most of which can't be accessed from the running program itself. I would love to see a cross-browser way to hook into these sorts of things without extensions or at least with standard APIs. Overall this would be much better for us as coders. And this would open the way for all sorts of cool tools. Consider V8's live code reloading functionality. But imagine if it worked cross-browser and could be called from the program itself. Your webserver could send a signal over websocket, and you could perform hot-swapped deployments of your webpage, and all connected browsers would be updated. The browsers could be customers', or they could be inside that mobile device that's a pain to debug. It would also be much easier to prototype new dev tools and ways of coding. For example, programming against Chrome's extensions APIs (as great as they are) is somewhat limiting - last I checked you lack direct access to the embedded CodeMirror editor for example. There are a lot of security-focused restrictions. So people workaround this. They rewrite editors and file managers from scratch so they can get the desired flexibility (lighttable, brackets, atom, etc). Personally I love to see projects like MetaES because I feel like they are inching us closer to something that could be the next step.