>- "All of the spending tracking and other information is stored directly on the device, not Apple’s servers" - can't see how this will work in practice. If you lose your phone, do you lose information on historical purchases? What if you want them for your records? Perhaps "spending tracking" just refers to data derived from the transaction information... but then, couldn't you just recompute it?

You can back up your device to your computer (which Apple cannot access) or to iCloud (which Apple can access). If you lose your device, just restore from a backup.