The video talks about best practices to proactively create a user experience where purchase are checked using currentEntitlements that's what I can up with myself and have implemented in my app, and seems to work flawlessly. However the sync() method is not touched upon. To get my app through review I need to implement a restore purchases button, although a seamless UX is recommended. There's some info lacking here. I doubt if the sample app would get passed app review...

Just another remark: calling sync() does not trigger an App Store login prompt. At least not on macOS...