What is the international availability status for the physical cards? Are these going to be shipped by you and what are the rates? Also inorder to purchase Ethereum or the ERC-20 tokens are you going to allow users purchase them using their credit cards, that is, in order to load these metal physical cards with those tokens or ETH?
Practically I also think there's going to be some form of delay or time factor involved in receiving these cards if it's to be used "around the world". There's shipping time and probably legal concerns in countries that have made cryptocurrencies illegal. Do you have any sort of business plan to service users living in those countries?