"Banks have typically been good about walking the line between convenience and security.”
No, they are effing useless. Buy a train ticket then when you get the card back buy another one, because, I don't know, a friend doesn't have change or something (i.e. two transactions within a short time) and your card gets blocked. If a merchant in Outer Mongolia where you've never been or have any intention of going charges your card they wave it through.
And if your contactless card gets stolen and you get it cancelled, it can still be used by the thief for contactless payments until the expiry date.