This is a nice idea, but what do you do when the OS tooling is not that good? macOS is a good example, they have OS level sandboxing [0], but the docs are practically nonexistent and the only way to figure it out is to read a bunch of blog posts by people who struggled with it before you. Baking it into Node means that at least theoretically you get the same thing out of the box on every OS.

[0] https://www.karltarvas.com/macos-app-sandboxing-via-sandbox-...