I thought CC Insurance was international only?
I always have cc insurance and also a paid TI for international trips (including NZ) but never bother to buy a policy for domestic.
I have paid private health insurance so if injured or ill on a domestic trip am fully covered for medical anyway (plus Medicare safety net below that).
Apart from airfare don't really have any prepaid expenses for domestic, so not much to lose if I can't travel as planned.
I'd always have enough savings or points to get another domestic flight home, or an extra hotel night. Any work travel is insured.
In hundreds of domestic trips I've never had any unexpected out of pockets (no extra nights, injury) so think I'm well ahead, the savings of not buying a domestic policy over the years will fund another hotel night if ever needed.
FYI if they call westpac helicopter to extract you (say you fall off a cliff in the blue mountains or get swept out to sea in a rip) that is charitable not billed. I would not expect family to stay on if I was in a regional hospital, it's very unlikely they would have been travelling with me anyway.
Only reason for domestic insurance would be if you are hiring a car and don't take out the rental insurance, but irrelevant to me.