story
The irony is that if you write a desktop app at one point, you will soon learn about all the things that Chromium doesn't do for you. Want to run some kind of privileged operation (since disk benchmarks came up)? Tough luck, there is no special pass for you on macOS just cause it's Chromium. And with the app sandbox, there are now lots of things that are privileged. This story repeats ten times for every OS you want to support, regardless of using CSS for your UI chrome.