1) I'd call it a runtime environment, not a framework. But then people seem to be throwing the word "framework" at everything now DESPITE the negative connotation piles of crap like jQuery and Bootcrap have given it.
2) If all you know right now is client-side web development languages, it's the fast-track to making a cross platform desktop app.
The question is if you should choose it over nw.js -- and that comes down to your needs. Electron has somewhat better (IMHO) docs, a more helpful community (where people will ACTUALLY try and help instead of trying to blow smoke up your arse whilst trying to sell you something), and if you're going to use webframe/<webview> their implementation is a bit more robust exposing more of the underlying blink object.
With either electron or nw.js, if you can build a website and a basic command of JavaScript, you can probably figure out how to use it.
My advice would be to just dive straight into the documentation and get going...
Unless you don't know HTML, CSS, and JavaScript, in which case learn to build interactive websites first.
Side note -- I am a bit pissed with them though they've gone NPM on the distribution model and made it harder to find the standalone installers which are a thousand times simpler.