If it's the latter, does that mean that the card rewards for Apple Card will get worse?
Can it really get worse? All they do is a 2% cash back if you use Apple Pay, and 1% if you use the physical card. Ok if you buy directly from Apple it’s 3% back but that’s hardly “good” - you get a couple of bucks for buying an AirPod.
The partnership between Apple and Chase is not new, even though this particular credit card product offering is. There is another quite popular form of payment Apple has supported for years which necessitated this partnership to be established.
the card rewards for AC were pretty awful in the first place. It's only useful as a store card that offers 0% financing.
the deal is probably more in favor of chase when it comes to the fee schedule and various issuing bank and interchange fees (ie, the ~2-3% that card networks charge to merchants)