Seems like Electron would make a stronger foundation than native toolkits for Emacs-style flexibility, extensibility and composition. The DOM, for all its faults, charts a solid path between being flexible and still being structured, all while making it easy to change and extend from the outside. I've found it's much easier to write a browser extension that adds functionality to GMail—even without GMail actively supporting extensions—than it is to write a similar extension to, say, the native Outlook app (even with explicit plugin support from Microsoft).

I haven't paid much attention to the Electron world myself so I don't know to what extent anybody is taking advantage of this, but even if they're not, I expect it would be easier than with alternatives.