Is it discrimination against US coin currency or people? You decide.
I frequently use the neighborhood health food store and know most of the employees by name. I went there to make a purchase.  The store had very few shoppers in it at that time.  I had change in my purse and thought I would put 16 quarters and 10 dimes towards my cash purchase.  I went to check out at the customer service counter and made neat little piles for the clerk I know well.  She informs me, “We are not supposed to do this but I will this time.”  I said, “Why? I am making a purchase.”
She informed me that the policy is really for homeless people who come in and pay for food with lots of change because it holds up the lines at the cashier stands.