When is null useful? has been closed as primarily opinion-based, and I can't understand why. Look at the first answer:
For example, if you have a model where you aim to produce little or no garbage, Optional is not an option and
nullproduces no garbage.
This is a perfectly factual and helpful answer, and doesn't seem opinion-based at all. I don't really understand why this is not a valid question. Can I get an explanation so I can improve my questions in future?