These cafeterias are located in the city (just like a restaurant would be), creating jobs in the city (just like a restaurant would), paying good wages and benefits to these people (unlike most restaurants would).
Absurdity of this proposal aside, most food service workers in these cafeterias are contractors who are not paid well and receive shitty, if any, benefits.
Also consider that workplace cafeteria jobs generally have fixed schedules with weekends off.
The smaller catering companies, with <30 employees aren't usually too different from a restaurant, but the big ones are run by corporate bean counters, where everything and everyone is just a number in a spreadsheet.
I guess it's no different from your local mom & pop Italian restaurant vs Olive Garden in that respect though.