To quote R’ Shaffier (https://jdonations.mapletime.com/shmuz25/)
Why is Amex doing this?
For them it’s part marketing, part their way of encouraging
people to give. They figure if people use their Amex card for
good causes, it makes them look good, and makes for more
loyal customers.
The bottom line is that this is a chance to donate $25 and it won’t
cost you a penny!
…
PS- This is American Express’s way of giving back to the community. You simply donate $25 to the Shmuz on your AMEX card, and that amount will then be refunded to your credit card. It costs you nothing. And the Shmuz gains!