It isn't about efficiency. It's about giving stuff away for free versus charging for it. As one guy above put it, if you lay out a bunch of hotdogs on a table

It isn't about efficiency. It's about giving stuff away for free versus charging for it. As one guy above put it, if you lay out a bunch of hotdogs on a table and let people take them for free, you'll give out a whole lot more than the guy next to you who is charging for them and handing them out one by one.