For all its advantages, Bitcoin has one major drawback: it's rather hard to spend. While the digital currency has legs in online marketplaces like Overstock and Square Market, few brick and mortar stores are equipped to trade in Bitcoin. Special ATMs help a little, but there has to be a better way. Xapo, a crypto coin storage vault, thinks it's found one: the Bitcoin debit card. Xapo's card promises to work exactly like your bank's plastic -- authorizing transactions by checking the requested charge against your account balance in real time. If the sale is approved, Xapo automatically sells a comparable amount of Bitcoin from the user's wallet to cover the purchase. Xapo says the card should be an improvement on the Bitcoin pre-paid cards that already exist, which require the user to manually refill their plastic before hitting the town.