$379, not $399. There's an optional $69 2-year protection plan, which would cost $99 from SquareTrade. It also comes with a $50 Play Store credit. If you would've spent the money on the warranty and Play Store anyway, that makes it a $300 phone.
I think they meant that, because the Google provided protection plan is cheaper, you're saving money, assuming you're going to get the protection plan either way.