ChatGPT on macOS isn't built with Electron, at least the last time I checked. Just checking the linked frameworks shows that it links against macOS AppKit and the Swift libraries.
From a user perspective can definitely tell too, it's a polished, fast desktop app and has all the UI details one would expect from a native app.
From a user perspective can definitely tell too, it's a polished, fast desktop app and has all the UI details one would expect from a native app.