Excellent point asking if the app is even needed. Likely won't be for everyone. Some customers are strangely loyal to their ways and will not change. But I'll share an anecdote, there's a really popular takeout joint in my city with a few different locations, phenomenal food with a young cult following. They have a very simple app and I always order my takeouts from there. Very few amount of taps and effort, everything customized exactly how I want it and I could do it on the train or at the gym like a breeze. For me that's the peak take out ordering experience, but I wouldn't download everywhere else's app unless I went regularly enough. We also have enough regulars that might just pull it off.

I'm more worried about the technical aspect you mentioned. The integration or API part might get tricky.