you nailed it! A consumer should only be able to set an object's state at initialization (via the constructor). Once the object has come to life, it should be internally responsible for its own state lifecycle. Allowing consumers to affect the state adds unnecessary complexity and risk.

Making a property writable adds an order of magnitude in complexity. In the real world it's definitely not realistic for every class to be immutable, but if most of your classes are, it's remarkably easier to write bug-free code. I had that revelation once and I hope to help others have it.