It depends a lot on what you want and what you will use.

We have it, but I chose to go public for DS' birth cs I could choose my own OB, it still didnt cost me anything (my GP practices obstetrics) and had the continuity of care.
I know a lot of people who dont have it, and save the same amount of $$ that it would cost them each month in an account that is used to pay for their health/medical expenses.

I like to have it for the security that if something happened to any of us that needed serious medical attention we wouldnt have to go on a waiting list for aan "elective" procedure. Also DH has a history of heart problems in his family, wears glasses and I have the orthodontic stuff like you did - we had PH and my braces were off and all treatment finished by year 7 at high school.

As regards family cover and giving birth, a lot depends on the insurer. some will cover you on singles cover for a singleton birth and upgrade it to family on the day of the birth, others required you to have family cover already, and some have minimum amount of time you need to have had it for prior to the birth.