Yes. It is by far the easiest way to make a nice looking cross platform app. If you can't handle the extra RAM you are always welcome to use the CLI
Depends on how much one actually bothers to look around.
I guess anything goes helping Google to spread Chrome all over the place, it gives them a warm feeling.
The statement still holds. This one is just the status quo
I understand that you're basically running a Node.js instance for each app, but why is that more insecure than running, say, a GTK app? Since GTK and Node.js are written in C and C++, respectively, my gut instinct would be to assume they're equally likely to have security bugs.
(Electron offers sandboxing too, but you're likely to actually want to use the OS features so it's not as simple as always disallowing the access.)