In order for the instant moving of funds between protocols to be possible, Smart Savings requires using a smart contract wallet that is in control of your funds while you’re supplying them within Smart Savings. Each user, or each account to be more precise, is associated with its own smart contract wallet that no one else can control and you can withdraw your funds from Smart Savings at any point in time. Overall, the experience is the same as when supplying directly to a singular protocol.
More specifically, the smart contract wallet used by DeFi Saver is MakerDAO’s DSProxy, an audited and battle tested smart contract wallet that they developed for their CDP system. In case you ever created a CDP, that means that you already have a DSProxy associated with your account and DeFi Saver will use the exact same one. If not, DeFi Saver will create one for you.