I work for Google and live in Switzerland where food is really expensive so my situation doesn't generalize well.

However, if 1) I cook all my food, and 2) try to have a healthy diet I spend easily the equivalent of 30USD/day. Going to a restaurant sets you back around the same amount per meal.

So, assuming I work 200 days/year going to the office and get free food would save me 6k USD/year (also assuming I cook 100% off my meals). That kind of money would pay for holidays or other stuff.

Finally, my back of the envelope math didn't include the time I spend cooking and all the "premium" stuff I get at the office like fancy drinks and snacks, which I usually don't buy when WFH.