Some of the new features most people aren’t aware of us that I used recently :
WebXR, make a Web page immersive and work in the browser of VR/AR headsets, e.g Meta Quest, Lynx XR1, Apple Vision Pro, etc
WebBlueTooth, connect to a BT device, e.g a Lego controller in order to move actuator, data from sensors, etc
WebUSB, connect a device and update its firmware, e.g SmartWatch, mechanical keyboard, etc
GamePad API, use a gamepad or joystick to play from a browser window
Realms in JavaScript for “better” sandboxing, it’s a relatively new feature of the language so the engine must be updated
So… sure none of that really helps to read a 2D Web page (like this one on Lemmy) but they pretty much all help to achieve better cross-platform support. By using the Web rather than native to connect to hardware then it is instantly delivered without having any OS specific driver to build and install. Practically speaking it does make the browser increasingly complex but IMHO it is worth it.
PS: I probably also used some modern CSS so there also the engine (which is ridiculously complex by the way) has to be updated too.