One very specific case where choosing one over the other might matter: **when travelling**. Some regions of the world only (or almost only) accept one or the other at cash machines. For instance, I was travelling on the huge island of Sumatra (Indonesia) & found myself not able to withdraw cash with my VISA. I did not have a MasterCard with me but had some "rescue USD" in a secret pocket. I luckily bumped into other travellers who had spare local money so I could exchange USD with IDR.