What happens when my phone & wallet are stolen and someone has complete access to my home?
The same thing as when they steal your keys at the same time.
This is very cool, but the tone of the title is a little misleading. Lockitron v1 was this exact thing, if I'm not mistaken. And that was released in 2009. So, the evolution of the key is here, just not as widely distributed. I actually think the new lockitron (which is an aftermarket add-on to just about any deadbolt) is poised to be more successful given it's much much easier for renters (a group that's getting larger every year in the US) to use.
From what I understand as a backer of lockitron, is that it replaces the deadbolt, similarly to this, but it is ONLY controllable via the app.
This seems to have far more: touch control as long as a control device is present, ability to detect whether the 'owner' is on the inside or outside of the door, a smart-keychain that functions just as the app allowing you to lock and unlock by touching the outside of the lock, etc.
It seems far more robust.