American Express has started paying its cardholders to use Apple Pay.

Yes, you read that right.

Yesterday, Amex started promoting an offer that pays its cardholders in Chicago $5 to use Apple Pay at “participating concessions” at the United Center. Cardholders need to make at least $5 of purchases with Apple Pay to qualify for the $5 statement credit. The offer is only good on Amex credit or charge cards, not prepaid cards.

It is unclear whether the offer will be extended beyond Chicago.

There are two possible explanations for why Amex is making the offer, which is clearly a marketing test: 1) it wants its cards loaded on Apple Pay before other cards; and/or 2) Apple Pay usage among Amex cardholders is lagging behind expectations.

This is not the first time Amex has resorted to paying its customers $5 for things. Last June, Amex started paying its cardholders $5 to give the financial services company their email address.

Nevertheless, we will point out that there are signs, however faint, that the Apple Pay whirlwind might be ebbing. Note the Google Trends graphic for “Apple Pay” below, which indicates a waning interest in the pay vehicle, at least from a search perspective.

The Amex offer ends April 27.