Depends how you look at it.

Here in China (major cities) delivery is often free and when buying from delivery apps there are additional discount available that you can't get when visiting the restaurant.

So basically it's often cheaper to get food delivered to your home than going to the restaurant itself.

In Greece, delivery in all stores is free (ie included in the price). To go from "free" to "3 EUR" when the average order is 5-7 EUR is unworkable and you'll never be able to compete.

Pretty much everything else is under 1.5 euro or free.

Depends on the economics. The food delivery companies take around 25-30% here in Finland (Wolt & Foodora). If the delivery fees were free, I'd order more food and Wolt would get more of the tax they charge restaurants. And maybe the restaurants can make up that loss by having more orders.

Delivery prices are astronomical here. For something 5min away with car (assuming no traffic) I have to pay around 7.90e. For something 1 minute drive away I pay 1.90e. Then there's ranges inbetween from 3.90 to 5.90.

My experiences with Wolt are that the food comes in a car and is not warm.