I think I read somewhere long time ago that Capture One is also using Qt for GUI, though cannot find this anymore, so probably not true.
CoreImage - GPU accelerated image processing out of the box;
ML/GPU frameworks - you can get built-in, on device's GPU running ML algorithms or do computations on GPU;
Accelerate - CPU vector computations;
Doing such things probably will force you to have platform specific implementations anyway. Though as you said - makes sense only in some niches.
I won’t try to claim that Electron and friends have no place is software development but we absolutely should be pushing back harder against stuffing it everywhere it possibly can be.
Every modern desktop uses webviews in some capacity. macOS renders many apps with webviews, GNOME uses gjs to script half the desktop. The time to push back was 10-20 years ago, it's too late to revert now.
Meanwhile on Windows major features like the Start menu are written in React.
Worth noting that WebKit webviews also tend to be more lightweight than their Chromium brethren.
I don't think gjs is a webview. It uses JavaScript, granted, but binds to a native toolkit, not to DOM and CSS.