Diversification. They see bitcoin as a potential move from regional state-based loans and services to capture a larger audience and to service its hispanic customers more broadly, remittance especially, also competition, and longterm collateral because of rising interest rates. Fractional reserve doesn't just mean they issue money they don't have, but more specifically money they can't access right away. FDIC insurance ensures bank runs are capped, but at $250k, this incentivizes institutions and large capital pools to hold Treasuries instead. But if BTC moons, you can see how this stretches their coverage dramatically.