You only need to make your Hotspot active for 1 hour per day to qualify for payment. We
will pay you for each device that you use to contribute to the Global Network. We aim to pay you
enough to cover all or part of the costs of your internet supplier and mobile phone supplier.
You decide how much data you wish to donate.
This two don't mix too well, people may need more explanation. It's good that you thought on this to avoid abuse (use of other's monthly data plan in an hour), but also somebody may set the hotspot for 1h and only 1 kb of data, making it actually useless and this has to be prevented.
Another issue is the trust - you'll have to somehow prove that your app doesn't do more than you claim, for example selling some more personal data than the users would like. Will the source code be available for review?
Overall I like your idea (although for EU residents you are a bit late), good luck!