For the shop owner(s), making the economic case for having a card merchant account comes down to several factors:

- Size of typical transactions - Volume of transactions per billing cycle - % of charge-backs per billing cycle - Charge-back volume compared to revenue - Anticipated volume & revenue gains with the additional card buying channel - Comfort level with dependency on 3rd-party accounting - Comfort level with 3rd party data mining - Comfort level with necessary technologies - Additional management overhead due to accounting and card accouterments

Offhand, there are a variety of scenarios, esp. for boutique businesses in urban environments with ready access to ATMs, where a cash-only policy makes good business sense.