The point of good state management is to ensure that each instance has a single home. As soon as you start passing instances between functions/modules/components, you're leaking abstractions between different components. Sometimes it is appropriate to do this, but most of the time it's dangerous. Components should aim to communicate as little information about their internal state to other components as possible.
Now you've got an immutable id string, you can access as easily as the bare one, but now you can't mix it with other types of IDs, so you won't pass it to something expecting BarId by accident. As a result - no black boxes and a clearer design.
A variant of this is the cause of many Linux kernel issues. They basically had to cram it into macros to prevent passing real/kernel pointers to userspace by accident, because pointer is a pointer is a pointer.