The Smart Hub and Smart Cameras aren't too smart as they all can't talk to each other and save video on the hub. They all connect to the same Wifi and are able to all connect to the same app and cloud service, but not the hub. 
Tapo, do the right thing and write the code within the app and allow users to have the option to save all cameras to the hub, a pc or make the basic cloud service free, then you will actually have a smart security system. Currently it's only a complete security system if we use only battery cameras or subscribe to the cloud, which for those of us that started buying your system before the hub or cloud were available or choose wired cameras. It's coding anything can be done. You give the option to download manually on the app, allow users to set download times or options to do so with each recording. Having SD cards on each camera really isn't secure, a hubs better, and yes the cloud is best if users want, but not all do.