Hospitality is a wonderful thing, but the nitty-gritty of how it should work can get complicated at times. In theory, all somebody has to do to host a good party is plan an event and create a good atmosphere, but the tiniest of details can end up having a huge effect on whether they are successful with that or not.
You don't have to be an event planner to acknowledge that refreshments of all kinds are a big part of party planning. Anybody who RSVPs is likely to want to be greeted with some kind of spread. Whether you do everything yourself or propose a potluck, there are multiple ways to go about this.
One thing is for sure: it is easy to turn a good party into a bad one when you start to get weird about the food and drink. Every host has their limits, but ultimately, they benefit most from engaging in some well-managed generosity with their guests. Nobody likes to attend an event where somebody is obviously being stingy, for whatever reason.