That person may have covid, and is reducing the spread. In a big store situation masks will definitely reduce the spread of a virus. In a closed room with lots of people, probably will do little. I had covid a week ago, and started wearing a mask when in a store. Felt a bit stupid, but it was for other people not for me.
So.....in spite of the FACT that masks do NOTHING to ameliorate the reduction of a virus, you want us to know you wore your mask to save others.
What a good boy you are.