AppJs, Electron (Atom Shell), and similar schemes get around the severe limitations of fatty, gristly, clunky, ajaxy web pages as rich clients. They do this by embedding the Chromium rendering engine along with Node.js or Io.js into a runtime that bypasses the use of HTTP as the glue between them. This moves the "server" right into the client.

The result is yet another way to write high performance, cross platform, stand alone, desktop applications.

Example: Microsoft leveraged this when they made Visual Studio Code, a cross-platform IDE. See Microsoft Launches Visual Studio Code, A Free Cross-Platform Code Editor For OS X, Linux And Windows if you forgot about this announcement last Spring at Build. Sadly, it isn't a RAD tool for desktop development itself, sticking to "dark world" text-bound technologies (JavaScript, TypeScript, ASP.Net 5, etc.). But that's just the market they chose to target with their first venture.

Of course these schemes suffer from the same problem, yecch, ptui: JavaScript.

Love it or hate it (or put a funny face on top of it using a preprocessor language like TypeScript)... JavaScript engines have gotten pretty fast and it is becoming almost unavoidable.