Tim say this, because while iOS8 is all sweet and surgaryy with pass-lock lock now also protecting WI-Fi-passwords etc, not just the key-chain in iOS, and this all sounds great, but all bets are off with iCloud, and since most users use iCloud anyway as a convenience to restore their devices back how it was easy, and iCloud backups, then the user is screwed anyway by a typical government warrant
That's probably 98% of us right there ... including me.
Maybe, never use iCloud ? *shrugs*
I guess this is what people we mean by "security through obscurity"
It's secure as long as you keep in on your device, which i like how Tim constantly emphasized this as through users were getting something "special"