You keep bitcoins in your account, whenever and wherever you use your card just like any other visa card, corresponding amount of bitcoins is put aside by xapo until that transaction is settled. As far as the card owner is concerned the transaction is over since You get what you want, the rest is handled by xapo. I think employers should deposit salaries directly to the employees' xapo accounts. :) btw, if I am not mistaken the exchange to your local currency is calculated at the moment of the purchase , TRY-->USD $--->BTC .