In the past you could get free travel insurance from your credit card provider only if you paid for your flights and/or accommodation with the credit card.
That is no longer the case.
As long as you hold a Gold, Platinum or Diamond credit card from CBA, you are entitled to free travel insurance for trips of up to 6 months duration (Platinum and Diamond) or 3 months if Gold.
There is no need to buy your airfares with your credit card - in fact there is no need to spend a cent on the card to get the insurance.
You do need to activate the insurance before you travel here:
A $250 excess applies to claims for Dimaond/Platinum cardholders ($500 for Gold)
If you need transit insurance (protection from injury while on transport like planes, boats, etc) you must pay for your "trip" on the CBA card - see page 77 of the PDS.
I am doing a 70 day trip shortly. Most insurance is $200+ for 70 days (and many insurers wont insure trips that long).
Flight Centre quoted me $429 for insurance.
Although the excess here stings a little, it's not much more than the premium would otherwise be.
Free travel insurance with cards is nothing new, but the mechanism for this is and so is the nil spend requirement. See previous post for prior comments/discussion.
This seems like a question for CBA customer service