[Kurtz79]

Technically you could use the same application (as in, same UI and features) across the three major OSs.

(Although you could make the same argument for something written, say, in Java)

[kartoffelmos]

The notion that "you could use the same application across the three major OSs" is the feature – the feature is not that it uses Electron. That it uses Electron to accomplish the feature is incidental.