According to @cas_abbe, Aave and other lending protocols assume 1 stETH equals 1 ETH for collateral purposes because users can ultimately redeem stETH for ETH after a waiting period (source: @cas_abbe on X). According to @cas_abbe, stETH often trades at a slight discount to ETH in secondary markets, creating a stETH/ETH basis that diverges from the 1:1 collateral assumption (source: @cas_abbe on X). According to @cas_abbe, this market discount is the second key reason in his analysis and is relevant for traders evaluating borrowing power and potential liquidation dynamics when using stETH as collateral (source: @cas_abbe on X).