MP Shopping and MP Credit Card
 

Whenever I use the MP shopping portal, I am presented with the following message:

"Remember to use your MileagePlus credit card. Cardholders are eligible for increased miles offers from participating stores in addition to earning one mile for every dollar you spend using your card."

I typically do use my MP Select Card. However, I have never noticed any increased miles offers as a result of using my card. Is this some special Chase benefit that I'm not receiving but should be receiving on my statement? Or, does Cartera know that I hold an MP card and is automatically displaying to me what those increased miles offers are?