My experience is different. If my wife goes to the counter and I order electronically, she is always done faster. This is doubly so if I use a phone app, because the app is painfully slow.

If it was just slow, I might put up with it. But the systems are broken. For example, it's recently changed, but the electronic order screen in the restaurant used to print a receipt with an order number. The bulk of the time the printer was didn't work - out of paper or something else. Then you had to remember the order number, or have an argument with the counter staff, or on occasions both.

The app is anything is worse. On several occasions I've had the app not clear my previous order after collecting it. I didn't notice. The result was a double order the next time around. If I did notice, it would take ages to clear the order because the app insisted you delete the items one at a time and it's takes seconds for each item. On one occasion I drove up, gave my app code to the cashier, only to have the restaurant claim they had no record of the order. I showed them their app on the phone saying it had been paid. They said they could not trust it. It took me 30 minutes on their web site to get the payment refunded.

One restaurant has recently fixed the printer receipt problem. They get you to enter your name now, and they call it out when serving the order. The printer has gone. It took, what, 5 years to recognise the problem and find a fix. I assume the same will happen with the app, but I'd expect another 5 years at least.

The reason the cashier is faster is partially because the app is slow, but also because the UI is different. The user friendly interface displays long lists with nice pictures the user has to navigate by scrolling. The cash register UI is designed for speed. It displays lots text buttons that near respond instantaneously. They could streamline the app interface a little, but you will never be able to hit the speed of a experienced cashier entering the order, or an AI doing the same thing. The app using an AI to process your voice order on the other hand could be just as fast. Maybe that is what we will get next.