"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Offering 10% Bonus When Adding Funds Directly to Apple ID
The funds can be used towards purchases on the iTunes Store and App Store, an iCloud storage subscription, and so forth.
To add funds directly to an Apple ID, go to Settings > Your Name > iTunes & App Store and tap your Apple ID > View Apple ID. Sign in if necessary, tap "Add Funds to Apple ID," tap the amount that you want to add, and confirm your selection. There's also a shortcut available at the bottom of the App Store.
Adding funds to an Apple ID requires having a valid payment method on file and is particularly useful for prepaid credit cards.