Credit cards and soap are both classified as commodities, but from a marketing perspective the similarities don’t extend much beyond that.
Soap is largely about the very expensive game of buying recognition and differentiation through brand advertising, product positioning and distribution. So in that space, the TUP Model applies: Volume can be influenced by the trial rate, user rate and package rate (Volume = Trial rate x User rate x Package rate).
The beauty of marketing credit cards lies in the unique dynamics of the product. Anticipate and address these dynamics and you can continue deriving income from the same customer over a lifetime.