And because I'm a software developer with a flexible work schedule paid hourly, the act of going to grab the food myself and not working for 30 minutes would cost me way more than delivery costs (even cooking my own meals can be more expensive when time is factored in, compared to food price at restaurant + delivery cost (for ~2 portions prepared in 30 minutes. Proper meal-prepping would be cheaper of course, but yeah I'm too lazy to do that)).
Also the food delivery services often offer discounts and with them it's sometimes cheaper to order the food than going to the restaurant and eat there. Yesterday I ordered with a 30% discount - I got a dish which would cost 10.80€ at the restaurant for 7.50€ including delivery.