In a way it really is, in part because HTML + CSS is the back door "universal native GUI framework" that various projects have been chasing for years. Because browsers and GUI elements in them are so important to modern computer use, every OS vendor has a vested interest in ensuring the default look and behavior of elements in their browsers are native (or as native as possible). As a result, if you can render your UI in a browser (or in a browser frame/view) chances are you can get a native looking and native feeling UI for your application with a well understood and robust piece of technology that will retain that look and feel even as the underlying OS changes around it.

Powerful, perhaps. Slow, for sure.

I don’t know. Resizing a window with complex ui in html tends to be faster than native guis for me. It haven’t tested this properly though.

I just use a fullscreen <canvas> and WebGPU. It's performant as hell.

Skill issue, I guess. /s

Performance is relative. Every electron app I have used has been slower than their equivalent native app.