The user (via their user-agent) should be in complete control of autocomplete, and sites that think otherwise are broken. Mechanisms to specify the semantic nature of a field are great; by all means, make it easy for a user-agent to know what to fill in. But "autocomplete=off" was originally invented because a few large sites (archaic bank sites of the same type that did browser detection and rejected any browser they didn't recognize) wanted to prevent users from using their browser to remember their password. That's not something the site should have control over.

Unfortunately, it's not just Chrome doing stupid stuff with auto-complete.

The latest Safari (bundled with Mojave) tries to auto-complete email addresses using your address book. That's not at all a bad idea, except that like most things Apple of late, the implementation sucks. When you give the input box focus, it opens up some sort of weird dialog prompt, which pulls you out of full-screen mode if you had it enabled. Really messed up our 3D web viewer.