With the market being as hot as it is right now, most agents will ask if you’re pre-approved before presenting your offer. There are upwards of 20 offers on all many properties right now, for example this one, which had 24 offers (3 my clients) and was listed at offers over $375k and sold for $530k with 3 offers over $500k.
https://www.realestate.com.au/sold/property-house-tas-st+leonards-137790302
In short, it’s insane right now and many agents won’t strongly recommend your offer to the seller if you’re not pre-approved as being pre-approved means that you’ve had a bank assess your borrowing capacity and all that should be required is a valuation which means a much quicker time to approval.