Thank you ACI & Chaos for bringing this discussion up.
There are obvious benefits to sDAI as collateral which @MarcZeller has brought up clearly.
However, there are risks. Creating a structural scenario where GHO can be minted at a meaningfully lower interest rate than the yield of a stable collateral will put pressure on its peg. Users may mint GHO against sDAI, sell it for (s)DAI, supply it to the protocol, borrow more GHO, and repeat this process in order to increase their yield. This will lead to an inflation of GHO’s supply without corresponding demand, putting pressure on its peg.
This risk could be minimized by listing sDAI in isolation mode (only able to borrow stablecoins with sDAI as collateral) and/or with strict supply caps.
Overall, I am supportive of listing sDAI as collateral, and suggest we work to minimize it’s impact on GHOs peg.