Hi David.
I have my cards in Wallet. Secure. Proof of purchase immediate**. Acts like a contactless Credit Card, therefore limited to £30 per transaction. No problems.
** The immediate proof of purchase came in very handy recently. My wife and I went to a local store, bought groceries, whatever. Went to Self Checkout. Paid with Wallet. At that very moment the machine crashed, so it could not spit out a paper receipt.
The staff could not get the machine to work. As there was no paper receipt, there was, in their eyes, no proof that I had paid. Choices offered to us were (a) rescan the goods and pay again. Bring bank statement to prove a double purchase. Get refund. (b) Leave the goods, and return with bank statement and get refund.
With a contactless card, we would have had no other option. Showed them the receipt in Wallet on the iPhone. Case closed!!
In fairness, that is very unlikely to happen often, but the instant proof of purchase is useful. It names the vendor, the amount and the time/date.
Ian
PS This proof of purchase could be useful in buses, trains, trams, underground etc, if ever challenged