While the delivery times are not great yet because a lot of items come from abroad, their inventory is now pretty extensive.
In these COVID times, I've been buying quite a bit of bicycle gear & parts and in many cases I could find stuff on Amazon at lower prices than AU specialist online shops. It certainly was not the case just a couple months ago.
I reckon Prime Membership in AU is now very worth it as you get free international shipping for orders over $49, in addition to free expedited domestic shipping and Prime video access.