Apple pay is limitless. The security is far better than with a contactless card as on the phone you need your fingerprint and the watch it needs to be unlocked, plus no information about the card goes anywhere near the retailer. The watch will lock itself automatically if it is removed from your wrist, so it cannot even be stolen and used.
https://www.apple.com/uk/apple-pay/
https://www.apple.com/uk/apple-pay/