Why does it even matter if you show the credit card type when the user is typing it in? If the first 6 numbers determine the card type, then handling card type can be done on the backend. Why make the effort to show users information that they already know, ie. card type?
It helps to display the card type while you type because then I know that I am typing something reasonable and I know that I am not entering incorrectly. Of course, the entire card number could still be wrong which can only be validated by the server/backend processor but overall, displaying the type gives a level of "instant" comfort. It also gives users peace of mind that they system knows what they are doing. Thin…
It might be better to let the customer pick their card type, that you could also better inform them that you do not accept their card type.