> every time that you buy things with your credit card the bank change the business a small fee, so in a way you are making the 'rich' more richer and the 'poor' more poorer.

I used to work for a small "mom n pop" style computer store, and did the cash drops most days. My understanding was that the cash handling fees were roughly the same as the card fees. Arguably card processing was cheaper for us,and less error prone (card machine hooked up directly to the till means I won't accidentally give the wrong change when I'm hungover, for example. )

Most of the time you see steep charges for paying by card (e.g. taxis) theyre related to tax avoidance - if you pay cash thryll just pocket it and not log it as a trip, whereas if there's a card payment there's a paper trail.