That's a good analogy to point out the weakness behind relying on encryption without secure boot but without going into the mechanism behind "making sure the lock can’t be replaced" people might incorrectly think "they're both about setting up locks and therefore they are linked" whereas "making sure the lock can’t be replaced" involves securing the environment that the lock is placed in, like "Make sure your hinges are not exposed so the door cannot be taken off its hinges from the outside and replaced with a seemingly identical door."