Of Indonesia's 270 million population, half lacks bank accounts but most now have mobile phones. Questions about compliance with Islamic law are a significant hurdle for the adoption of digital payments and other fintech services, industry executives say. Known as Sharia, the law strictly prohibits charging interest, or "riba", and clerics in Indonesia disagree on whether the popular cashback rebates and discounts given by digital wallets qualify. Social media videos in Indonesia on whether e-wallets are “haram” - prohibited by Islam - or incorporate "riba" rack up hundreds of thousands of views.

https://www.nytimes.com/reuters/2020/03/03/technology/03reuters-indonesia-digitalpayments-islam.html?searchResultPosition=5