I agree it's a great idea, but to be honest... how often do people go to their MAC counter? Like "regular", non-specktra, just go to buy my foundation, people? I have bags for Walmart and Publix, because I always go there. But places that I don't, I don't bother with the bags.
I have a Sephora one because it's free and I never used it. And don't plan on it.