A friend once lent his car to a neighbor for a weekend getaway, but he kept the title, insurance, and spare key the entire time. The neighbor got to use the car without taking ownership of it.
The difference between using Bitcoin and giving up ownership is an important idea, especially when people wonder how it can stay in cold storage while still providing value.
An honest answer starts with an explanation rather than an assumption. Trustless Bitcoin wallets, as @BabylonLabs_io describes, hold the actual Bitcoin in their own custody under script-based conditions on its native chain.
What can move in the ecosystems that support it is usually a representation token, a receipt that reflects that locked value rather than Bitcoin.
If this representation is recognized within the lending protocol, it could theoretically be used as collateral, while the underlying Bitcoin remains untouched in its wallet.
This is a critical point, not a technical one. The security of the underlying asset and the utility of the derivative are two separate questions.
plays a coordinating role in this broader security layer, although its inclusion, by itself, does not guarantee any specific external DeFi integration.
For holders, the real question is not whether it feels easy, but whether each layer between the wallet and any lending protocol is independently verified.