I'm fairly certain that Nest cameras do not allow streaming over your local network.
You can still use the cameras even without a subscription, i.e. watch the live stream or get notifications. This means that yes, they are absolutely uploading data to the cloud and storing it for some undetermined window. Paying for a subscription seems to just give you access to that history.
You can still use the cameras even without a subscription, i.e. watch the live stream or get notifications. This means that yes, they are absolutely uploading data to the cloud and storing it for some undetermined window. Paying for a subscription seems to just give you access to that history.