Mind you, there's (sometimes a little, sometimes a lot) more to Electron than a webview. Some apps are running quite a bit of un-sandboxed native code—sometimes even forking off other native processes†—to do what they do. Keybase is, IIRC, one of the apps that are quite large on the "native" side.

† I once designed a system that has Electron install an Erlang release to the client, register it as a service, and start it. The Erlang node runs a locally-bound web server; the Electron app then visits that web server. All the data-wrangling happens in Erlang land, with Electron just serving as an HTML renderer for the pages coming from the local server. And yet Electron's native side is essential, here, because it ultimately manages the Erlang release (installing it, updating it, etc.) Erlang doesn't have any good tooling for doing client-native stuff on its own; Erlang devs find the whole idea of deploying an Erlang release to a client machine funny.