I guess the issue is that to make such an app work you need to have a large network effect. If there aren't enough coffee shops on it I will never think about opening the app.
I used a popular app in Sydney. Sydney loves it's coffee and coffee shops and people don't mind shelling out $5 for coffee, queuing for it but the coffee has to be good.
A lot of people will go to the same coffee shop every day, near where they work, or perhaps on one of the train stations on their way. So if just that coffee shop has the app supported it that might be all they need. A single coffee shop could have it's own app and be all good, in theory. Although people often need marketing and re-marketing to remember about the app. So seeing an ad for Cloosiv on the train, then seeing the sign at their local will help them adopt it. A free first coffee helps as well!
To use the app, you have to know what coffee shop you are going to in advance - so there is an element of habit by the users. If you are in a strange area and don't know where to get a coffee you'd probably walk in, by which time you probably are better of queuing although maybe the app is still faster. Unless you are using the app for discovery. If I am in a dense area I can find a coffee shop easily. But if all the coffee shops are listed and I am in a area with few shops it could be a useful way to find my nearest. But you'd need a lot of saturation for that - a bit like Uber has nowadays but not at the beginning.
Another aspect is the move towards bringing your own cup. This is awesome for the environment, assuming people aren't throwing away the permanent cups! Usually there is a small discount for BYO cup.
Hopefully it should cater for that, but to do so would require them waiting for you to appear before making your coffee - negating the speed benefit but there are other benefits such as loyalty points, not needing your wallet and so on.
