here in Italy, 100% of the cards for buying phone prepaid credit are scratch cards, instant lottery tickets are scratch cards, etc... I've never heard of someone buying a card that was used and re-printed with the metal layer.
OFC I must say usually you don't buy them from other people but from "commercial entities". Still, if one can quickly check if the money is in the process of being double-spent, this is still way more safer then cheques.