Synchronizing with Apple ID is the same way to save your progress as connecting via Facebook.
It is a very handy feature that ensures your progress is saved. It allows you to play on different devices and restore your progress even if your device has been lost or broken.
Just open "Settings", click on "Apple connect" and your progress will be synchronized with your Apple ID profile.
And if you want to play the same game on different devices, just connect the same Apple ID on both. In this case, your game progress will be synchronized correctly.
We accept your choice not to use Apple ID/Facebook, but this is the only way to save and transfer your game progress/coins/gems to another device.