$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.
the protection plan is not included
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.
Wow...really do not like the forced purchase of $50 of app store credit.