Should probably add that in-store customers are third-class citizens; drive-through orders without customization get priority.
Interesting. Can they be certain that the device from which one places the order, is also taken along for the ride? Some people might order from a separate phone or tablet, which stays at home. Perhaps all of this customer's devices have the McD's app; and any one of them may trigger the order, by approaching the store.
Crazy invasive. Guess they want to see how far you drive and what route you get to get there.
It's best to get your order code, leave your phone at home and just pull up and say "I have order EM14..."
I once ordered ahead using the mobile app at a Starbucks. I got out of my car, only to find the doors locked, as they closed early for some reason. So I had to get BACK in my car, and sit in the drive-thru queue, just to pick up my already-completed drink, which I found infuriating. (actually, what was infuriating was that I really only order at that location to use their restroom, which of course was an option unavailable in the drive-thru for hygenic reasons)
At the drive-through speaker spend 10 seconds saying the code instead of 90 seconds ordering, with no chance of mistakes. The line still needs time to move, so the time savings isn't as big as it sounds, the order accuracy is what I appreciate.
You might save another 30 seconds at the payment window, they ask if you had a mobile order and then give you the receipt.
If the line has moved too efficiently, you will receive your drinks and be asked to wait in a reserved parking spot. This is the "time-out corner" for patrons with too many customizations on their large order, its still more convenient than picking up inside. In 5 minutes someone will bring the rest of the order to you.
The app has "20% off orders over $15" as a large incentive to use it.