McFerson states that consumer apps like Coinbase, Robinhood, and PayPal are the future dominant interface, while DeFi provides the backend liquidity. He cites Spark supplying 80% of the capital for Coinbase's Bitcoin borrow product. These fintechs can scale lending products rapidly without straining their own balance sheets by tapping into DeFi liquidity (Spark's $9B). This "DeFi Mullet" model improves their capital efficiency and product margins. Long major Fintechs integrating DeFi rails for backend liquidity. Regulatory separation of banking and crypto activities; smart contract risks in the backend protocols.