An interesting quirk of being a stablecoin issuer is that you have no opportunity cost for protocol-issued idle assets.

You can see this with the difference between USDC and USDS/DAI markets. All 3 of these markets return roughly the same for the Spark Liquidity Layer.

The USDC market uses the Deposit APY (4.96%), but the SLL uses the Borrow APY for USDS/DAI (4.92%/5.09%).

If you want an integration with the SLL, you will naturally get a cheaper rate using USDS!