Alphabet is not going to directly own any of the data. The proposals have been that it would be owned by the city, and only made available to partners in limited ways through a process with government oversight.
Snowden very clearly demonstrated the issue with exactly this sort of situation.
This description is not reassuring in any way.
What kind of data are they collecting?
The entire project will be a giant social experiment that would make BF Skinner cream his pants. There is not one bit of info about the residents that they wouldn't want to have. Every doorway will be fitted with state of the art facial recognition. Google will know everything about who comes and goes and why. They will know how often you use the bathroom and nag you when you keep the lights on. But, most of all they will know how you think, and how your thinking affects your actions, and which of those actions they can monetize.
Wow that sounds scary! can you link to any documentation/media coverage about this level of collection?