Am I weird that I enjoy HTML/CSS for GUI and Layout? With CSS grid of course. Hell I love Godot, but the fact that you can't do something as simple as give a component a max width is so annoying.
WASM can help, but the webdev ecosystem encourages developers to use fat JS libraries for most tasks.
Your browser prototype will probably start to chug once it grows to the point that it needs to juggle >1000s of objects. Native apps have the potential to be much more efficient and responsive.
They also tend to work better and more consistently on older/cheaper hardware. I think that every website developer should use a $200 Chromebook for development at least a few weeks out of the year. Most of the world is not using a new M2 macbook, and it's easy to lose sight of that when you spend your time working on new features.