[Vivtek]

I'll go one further on your first paragraph: I'm pretty sure I don't want something implanted in my arm that lets Google identify me.

Passwords may have insecurity - but they also permit anonymity. I think people haven't even started thinking that far yet.

[guard-of-terra]

But do you want something in your arm that lets you identify yourself to Google when you choose so?

[maxerickson]

Face detection has many of the same issues and there isn't much you can do about it.

[Vivtek]

True enough - but I don't have to make it rigorous with an RFID chip, do I?