The party-throwers know very well that everyone would get drunk on the booze being served if they didn't have some form of food laid out to keep the tummies of the revelers properly lined.
There's always a sleight-of-hand connected with everything the Moochers-in-Chief do....and the lavish PR about no lavish dinner being served doesn't mean that drinks and hors'd oeuvres a-plenty won't be served to the lavish guests.
Leni
The presidents pay for the food and drinks for their families or for all private get togethers.