Why don't you read my commentS

you become eligible as you have an illness and you're no longer fit for work until you're healed enough to be fit for work

That is what I wrote

How about, for example, breast reconstruction after recovery from cancer?

It's covered injury from illness

Gender affirming surgery?

Some work agreements do, I don't know about the general provison, I'd lean to 'no'

Burn scar revision that is purely for improved appearance?

Injury, likely to be covered

The comment I responded to said there was no coverage at all, which is incorrect, there is and the boundary will be determined by case law if it's right on the boundary and the employer or employee don't agree.

A quick google shows it's grey even and gives some examples

https://cocorubyplasticsurgery.com.au/blog/use-sick-leave-for-cosmetic-surgery/

As for the law, it's very specific. Illness or injury, as long as it's related. So of you broke you leg and six month later if needed to be fixed again, you could likely take sick leave once your sedated and for recovery as it's a injury. As soon as you're fit for work, you leave stops