Who are the most loyal group of credit card holders in your opinion and why? (Classic-Gold-Platinum)

I would say it would be Platinum, because they have proven their loyalty by giving the maximum business and transactions to the brand and therefore they have got the platinum card.

The ones who will get the best services from the host company will be the most loyal customers. Platinum Card Holders are the ones who are considered in the privilege banking and are entertained the most form the host so the Platinum Card Holders are the most Loyal of all.