Correct. Slippage would be an issue right now in my mind i.e. market orders on aUST to UST could be sizeable without limit orders. Calculating that slippage before it executes would be hard as well to know what exact amount to sell. Also in dev resources would be a sizable build and from my understanding, we need some minor contract update to the aUST. See this post regarding this - Suggestion: Short-term Enhancements for Anchor Protocol
So this might be something to revisit once more liquidity is in aUST-UST and updates to the protocol happen.