It's related to the concept of Mottainai (もったいない, 勿体無い) in Japanese culture. Where any waste is considered bad, specially related to food.
https://en.wikipedia.org/wiki/Mottainai
I wonder if this is why they tend to have plastic food displays at restaurant
https://en.wikipedia.org/wiki/Food_model
I think the plastic food displays are due to high uncertainty avoidance, so patrons can see exactly what their meal looks like before ordering. Yes you could use real food but the hassle of periodically filling the display case with freshly cooked dishes would be silly.