Your money goes toward lending protocols on the Ethereum blockchain. These protocols are essentially decentralized money markets. Meaning that lenders are backing loans in some capacity, or are matching you with liquidity to get a return on the assets you lend.
These loans are collateralized loans, meaning that the borrower has more than enough to pay the loan back. Traditional bank accounts that your funds go toward backing typically do not collateral.
The dollars you deposit go toward backing collateralized cryptocurrency loans. When people holding cryptocurrency want to extract the dollars from their portfolio but do not want to sell they take out a loan. In order to take out a USD loan on your cryptocurrency you must put up much more crypto than you would want to have in USD. Making these loans one of the safest to back.
You can use Etherscan or some other Ethereum blockchain explorer to view what is exactly going on with the exact funds your deposited.