I highly disagree with you. The less roadblocks you put in the way of a customer purchasing something, the more likely you are to get a conversion. By this log

I highly disagree with you. The less roadblocks you put in the way of a customer purchasing something, the more likely you are to get a conversion. By this logic, Amazon's One-Click purchase would be a failure because people "expect" to have to enter their address and billing info every time. That's simply not the case. Furthermore, some sites require this piece of data, some don't. I don't think this is like asking for the customer's email which they'd expect, selecting my card type is only present on ~50% of places I check out. (purely observational, no evidence to back that up) My point being that since entering your card type is not an expected piece of data every customer expects to put in for every transaction, they won't miss it to the point that they think your site is untrustworthy when it's not there. You have just made their life a little easier behind the scenes by not requiring them to supply it manually.