I don't personally need more than 1 virtual card at a time, but I was answering to the OP. Also the beauty of virtual cards or having many of them is that you can generate and use them on websites which you don't have high confidence with when using your card. Also it is useful for all sort of expenses where you want to set certain limit, e.g. AdWords, Facebook campaigns etc. I set︀ the limit and I am sure no more will be sent than the value assigned︁ to the virtual card.