Everything is clear, you know what's a button and what's not. Information density is also high, which is a good thing on a computer screen.
But the main thing is that Windows 9x felt responsive. The Windows widgets felt solid and performant, while "modern" UWP apps feel clunky and prone to breakage. And don't even get me started on Electron.
Edit. See OP's previous article here, he managed to capture what I was trying to say in more details, with nice screenshots: https://movq.de/blog/postings/2026-06-16/0/POSTING-en.html