Great question — answering as the UphillTech team:
I can speak only for Bulgaria, but I assume it‘s simular for the other two countries. Many cafes don‘t offer any food or just some cakes, people go there just to meet each other, to see and to be seen. Sometimes people stay there for hours and drink only one cup of coffee. They prefer to eat at home, because it‘s cheaper.
Full answer by Dirty-flow: https://travel.stackexchange.com/a/159491 (CC BY-SA 4.0).
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