McDonald’s in the U.S. is targeting market segments that either have low-price cellular data plans or are operating cellular devices in cars where coverage is often worse (especially for travelers!), which requires minimum server latency since you have to turn around those data packets instantly in order to queue them into their customer’s lowest-priority on-the-pole cellular pipe. Thus why they continue to provide a series choices that have such a high round-trip cost of user interaction: everyone wants to customize, no one wants to suffer a complicated UI, so simple serial dialogs served at minimum server resources per request it is. I would hazard a guess that the process fervor they design into their kitchen operations means that internet ordering is shown within the same metrics dashboard as store ops.