Sure, but in practice I think the idea is you run the browser full screen most of the time.

Huh? Chrome's fullscreen functionality is the same as any other browser's. And fullscreen hides tabs, so it's definitely not something you want to do most of the time.

No, it's by default a single window experience. You can get it to do standard, classical, utterly terrible overlapping windows. But it's not the default experience.

Not that it matters, really. Narrowing the field is just good practice for readability.