I think its certainly worth to download an app to save waste, however, I wouldn't pin peoples reluctance only on convenience. Nowadays it seems you have to download an app for literally everything, and I think many people don't understand why.
I've been in the exact situation as this woman with a place just around the corner: I just didn't get why I had to download an app in order to get the reusable box for my food from them.
In our case we have to make people download the app, as we can then track how long they've had it and this also ensures the return the box. However, we've also realized that not many people are as tech-savvy as we are, especially the older generation, so we need to think about other alternatives soon if we want this to be feasible. Did you end up downloading your app in the end then?
I didn't, I don't need another app to track me. A deposit is and should be enough to ensure the return of the item.
I think for many people the proposition "you need to download this app to do something for which the app is not needed" is a non-starter, also for tech-savvy people.
Another thing to consider is that I (and I guess many other people) are only willing to download an app while having wifi, since my data volumne in LTE is limited.
Yeah, totally feel you about the data and downloading the app, that's actually a really good point that I didn't think about! Unfortunately as the boxes are made from food-grade stainless steel, they are worth more than the 2 euros, maximum 5 euros that we would charge as deposit. The risk of people keeping them and losing the 2 euros is fairly high. On the other hand, making it more than 5 euros would deter people from paying, so it's a dilemma at the moment.
I've been in the exact situation as this woman with a place just around the corner: I just didn't get why I had to download an app in order to get the reusable box for my food from them.