So Google isn't trying to replicate Solar City, this is just an analysis tool if your home would be viable for solar panels. Almost like a middle-man for solar panel providers?
They are simply trying to reduce the resistance to solar energy adoption. If people can perform discovery and analysis in a fraction of the time, those who will benefit will more likely do it. Take a 10 hour process and reduce it to 30 minutes, for example. Same idea as a one-click checkout.