https://www.zellepay.com/press-releases/zeller-closes-2020-r... (Zelle® Closes 2020 with Record $307 Billion Sent on 1.2 Billion Transactions, Nearly 7,000 financial institutions are represented in the Zelle Network via their customers using the Zelle common mobile app, Achieving ubiquity with banks and credit unions: Nearly 500 new financial institutions of all sizes joined the Zelle Network® in 2020)
https://www.businessofapps.com/data/venmo-statistics/ (Venmo key statistics. Venmo processed $159 billion in total payment volume in 2020)
If anyone can plug into instant payments, your value as an instant payment provider that just does payments will fall rapidly.