> Why order when you arrive at the place?

Most of the time if I stop at a fast food place it isn't exactly planned out in advance. I'm usually already on the road or on my way home from some place.

Calling on the phone would also mean taking the time to stop and look up a phone number, and I'm sure most places would rather not take your order over the phone and would push you to use some app that at best will be used to track and spy on you and at worst could be used for discriminatory pricing. They can use the data taken directly from your device to decide what to charge you (iphone users pay 4% extra!) or they can use your phone number/device ID/whatever fingerprinting shit they're using and hand that off to data brokers and consumer reputation services to get detailed info about you like your income level and buying habits and use that to set the prices you'll be charged in real time. Zeta Global says you're rich, so all the menu prices pushed to the app on your phone are 10% more than what they show the guy behind you in line.