When I first heard of this as being a thing, my initial reaction was indeed something like "wait what? HTML and CSS in a desktop PC game driving the UI? No, that shouldn't be ... ".
But then I used Microsoft Flight Simulator 2020, was amazed by the graphics and performance ... and learned about how the complex and detailed cockpit gauges are using WASM/HTML/JS for rendering. No React, but still the "web technologies".
It dawned on me that this is apparently not exactly the weird, strange, bad performing, wrong-use-case, "why would you ever" thing I originally saw it as. Because it was working fine in that complex scenario.