On the day that Apple Pay goes live, SVP Eddy Cue has told the WSJ that the company “has a lot of work to do” on the service, suggesting that initial take-up may be slow – with in-app purchases making up the largest share of transactions in the short-term.

Although the list of retailers who have committed to Apple Pay looks impressive, it is far from comprehensive, with some big names missing – including the largest retailer in the US, Wal-Mart … 

We’re trying to do something that I think is a game changer and it requires a lot of people to play together. There’s a lot to do here and we have a lot of work to do, but it should be huge.

The WSJ notes that there are some big gaps on the card side also.

Macy’s, for example, says that around half its purchases are made using its own card, which shoppers prefer as it is linked to the store’s loyalty program. The store says it expects to add its card to Apple Pay “eventually.”

Corporate credit cards or prepaid cards aren’t accepted yet. Neither are retailers’ proprietary credit cards, so shoppers can’t use their Macy’s or Bloomingdale’s cards.

Eddy Cue believes that retail stores will make up only a minority of early usage.

It may be a full year before we see near-universal acceptance in the US. It’s next October that merchants who fail to upgrade to payment terminals which can read more secure bank cards with embedded chips will become liable for fraudulent transactions. At that point, it would make obvious sense to opt for payment terminals that support NFC payments also.

Apple Pay is currently supported by the iPhone 6/Plus, with older iPhones able to take advantage of the service via the Apple Watch once it goes on sale.