Thanks for the alternative code. I wasn't intending to merge disconnectedness with optionality, this was just the solution I came to.
Yes you would have to make your own non-Collection collections, that certainly is a downside.
I was actually hoping that this would allow us to make non-blocking lock-free structures. I'm not quite sure how it would work yet, just a vague idea. I think it would involve a Span or similar object.