The banks, even before the ban (which has yet to come), were keeping track of customers making payments to exchanges. In some cases, they customers a letter, erroneously citing an central bank order banning cryptocurrencies that had later been struck down by the Supreme Court. Despite no regulation, they've been denying services to exchange, preventing their cards or UPI payment addresses being used to transact either. Most mobile wallets followed suit.
The only option that remained then was P2P. I should caveat that I'm not sure I fully understand how that works in this case, though.
The issue is there's no real anonymous way to pay someone besides cash, unless you already had a crypto account with a wallet that had been filled. So an informal economy will need a safe way of turning physical cash into crypto and vice versa, in a regulatory environment where it may be banned to transact cryptocurrencies.
Crypto adoption is a gradual curve where people will only slowly start putting their savings or investment funds into a crypto account.
