...giving the ability to pay CRON cryptocurrency to the users, who perform activities.
Not really clear. What do you mean exactly by "activities"?
Is it something that your team defines, or any third-party could define "an activity"?
Will give you an example:
- I do provide some programming lessons to kids of my friends (or do some freelance tasks). Can I track duration of my services (i.e. using mobile app) and charge them in bitcoins?
Is your app suitable for that?