You're just creating a rod for your own back
Millions of merchants you say.. well if true, are there customers to match? There are less than a million Bitcoin users, most of whom only have amounts totaling a handful of dollars - and how many of those remaining plan to cash in their Bitcoin for overpriced products anyway?
We should remember that Xapo is less than 1 month old....there is probably a logistics problem on issuing the existing applications ( I am still waiting) assuming that the demand is as high as it should be..ergo no advertising..but when they are geared up to handle the expected demand .. as soon as they advertise the true advantage of Xapo..ie saving when spending in a foreign country, I can see the cards issued rising to 1 Million + in a short period of time..maybe 1 year..As a business traveler ....who would not wish to save 1-3% on the cost of spending? and the potential to have funds increase in fiat value by 20-100% ( if you are a believer)
Then add the un-banked who could now purchase online and save up to 66% that has the potential for millions more customers. I have frequently used my card to book tickets for non card holders to the point where I stopped as it became time consuming and aggravating..this is now an opportunity for them to increase their options and be able to transact on line with a debit card.