I got my card in Dec and right before applying from my iPhone, I unlocked my credit reports. Application went through without a problem and card showed up in my wallet. I then re-locked my credit reports. About 30 min later, I got a couple alerts from credit agencies that Apple-GS was trying to run a credit check, but were denied since my lock was on. No problems using the card since then.
I still don't see either the credit check or account show up on my credit reports a month later. However, I know the account will show up eventually. Not sure if credit inquiry will ever show though since it doesn't look like Apple-GS used it for my card.