Not only that, but when you depend on a system's webview you lose control of the environment your app is run in. With Electron, *you* as a developer decide which version of the Chromium binary is shipped to the user. And you can account for any bugs that may have been introduced in said binary.
When you depend on a system component like a webview you cannot guarantee all users are running your app in the same version of the webview. A user with macOS 13 will have a different system webview installed than a user with macOS 14, for example. Which will have different bugs and bug fixes.
(WebGPU should arrive soon to macOS' and iOS' webview btw 🤞)