coffee can be bought using zero confirms.. not due to there being no malle.. but the social study that a coffee shop would only have 1% of coffee stolen. and a coffee shop makes enough profit to cover that loss, and would not want to lose more money simply by upsetting customers by making them wait, thus losing future customers loyalty. in short its more about social loyalty to keep profits coming in, to cover potential losses.
And this is where you are getting things confused - if people can easily get away with out paying for something without any consequence then they will do it (that is human nature and I'm sure you can find many social studies that will back up this statement).
If you simply do a tx with an extremely low fee then it is entirely possible (even likely) that despite the tx being not rejected as dust it won't be confirmed before it is dropped from the mempool (and making blocks bigger isn't going to fix that either - a swimming pool will always fill up with water no matter how much bigger you make it).
Thus unless your coffee seller has checked that the fee looks good enough to confirm within a day (and how does the seller actually really know this?) the coffee buyer can enjoy their coffee and the next day be able to do it again (presumably they would probably not frequent the same coffee shop for fear of being caught but let's just assume that this person is a tourist and so doesn't care about coming back again).