Do you think that digital payments are enough to make India go cashless? I'm not sure that digital payments are going to do it totally. Even with the jump in Cryptocurrency, I do not think that a total digital monetary system will prevail anywhere!
I don't believe cryptocurrency will be widely accepted by India or any other government. The worlds' governing bodies are not about to give up control, and cryptocurrency has been linked to crime for far too long now. It's easy to hack, hide, and steal. It would be a precarious situation to base your monetary system on that kind of volatility