Credit Accounts are a primitive that enable on-chain composable credit. In their essence, Credit Accounts are smart contract wallets that are able to do anything SC wallets or EOA are typically able to do - i.e., store assets and interact with other contracts to swap, deposit and otherwise utilize those assets. What sets them apart is their ability to draw debt from Gearbox pools in order to create leveraged positions.
When a CA has borrowed from a pool, its solvency needs to be maintained. Therefore, all interactions between the owner of the Credit Account and the CA itself are passed through the Credit Facade - a sort of a filter contract that restricts the scope of actions available to the user, in order to ensure that the CA always has sufficient amount of (recognized by the protocol) assets to cover its debt. This is mainly done by restricting the set of contracts the Credit Account can interact with (through use of adapters) and defining a set of tokens recongized as collateral, with specific risk parameters.
As long as solvency is maintained, the owner of the Credit Account can use borrowed funds to implement any strategy they would by able to implement with their own funds on their EOA account (as long as the strategy encompasses allowed DEX pools and farms) - swap assets to other assets, deposit them to farm rewards, basis trade, etc.