I queried a contact at AC.

Here is the response I received.

"Good day,
Thanks for the question.
Firstly,if you have Altitude status;ie Elite status;
this supercedes the credit card application as it
is recognized as more important naturally.
Having said that the Infinite card has a designation
on your boarding pass.Instead of AC*SE for example,
the b/p will have AC*CC and this is how it would be recognized at
boarding.
For checkin presenting the card should allow you to checkin at
Executive Class."