The financial risk for power companies is so large, in fact, that they are unable to handle the risk without guarantees and subsidies from the government.
The old shareholders will get the equity in the bad bank. (In any restructuring, bondholders should do better than equity.) And the FDIC minimizes its risk because it guarantees the deposits in the good bank.
Snowling ticks off other advantages for Sallie: low interest rate risk (given government guarantees), profit growth expectations in the 15% range, a rich return on equity (net income divided by average book value) of 38%, and a cheap valuation relative to history and the broader market.