Some might argue that zero pricing is not sustainable for most businesses in the long term, as they need revenue to cover costs and maintain profitability. However, as a temporary or strategic approach, zero pricing can be used to achieve specific objectives. It would be interesting to see the comparison between different restaurants. For example, Deeween, a Pakistani restaurant in Vienna that asks customers to pay as much as they want for a buffet that cover 6 different dishes. It seems to be that there are many customers always crowded and such pricing methods could actually makes more profit than an ordinary business that runs with a fixed price.