Business case
What would two more visits a month be worth?
Then what you keep after cost of goods, the cash back you fund, and Zwipe's fees. Both views use your own numbers.
The opportunity
The load loop
A guest loads the card, spends part of it with you, earns cash back on what they spent, and leaves the rest sitting there — spendable only with you.
If the spend goes up or down
The same load, one purchase, three different spend-throughs.
Why it holds up
Keep these numbers on your record.
Saving them to a portal means the rep you speak to is looking at the same figures you are.