I understand the concept of making a native app to include using the native UI platforms. What you described is hardly more native than electron, which is basically a web app at heart.
Or maybe there needs to be a consensus on terms. Do people consider electron apps to be native? I would put them in some weird middle ground, but definitely closer to web technologies than native development.
The main complain about electron app is due to their bundling of complete web browser runtime, which is over a hundred of MB, not to mention the big memory requirements. By using platform's built-in webview component, your app size will hardly any bigger than the total size of the zipped html+js+css of your app. If you're going to use web stack to develop your desktop app anyway, might as well try using native ui webview first if you don't need any electron-specific feature.
With Electron, it feels more like starting from web and making it behave like a native app, from the standpoint of operating system app handling (task bar, notification). It can also fill a gap left by web for exposing a filesystem and other things that are native to some abstract computer.
Using WKWebView for UI is different in that you are starting from a native app and using web technologies to leverage code sharing and programming model of the user interface (js, css, html).
I think for this view to make sense you have to see web apps and native apps as fundamentally different things, which I believe they are.
From a capabilities point of view, they're native. You can access the OS api just like any other native app.
From a developer side, it looks like developing a webapp without the usual limitations of API access, albeit at an extra cost of marshaling or build-complexity.
There really is no reason to think of HTML/CSS/JS as Web only though.
Or maybe there needs to be a consensus on terms. Do people consider electron apps to be native? I would put them in some weird middle ground, but definitely closer to web technologies than native development.