MSpeedwax sells them (in North America) for USD 20. If the local Australian price is probably AUD 25, that still works out to AUD 2.08 per chain if you reuse each of the six YBN master links once. On the other hand, the connecting pins you linked to come out AUD 3.89 per chain. So, if you use YBN chains and reuse the master links once, then master links are going to be cheaper. Reuse them a couple of times, and the price gets much better.
If you don’t ever reuse the master links, then honestly I don’t know what the appeal of them would be, except easy chain repairs out on a ride (i.e., keep one handy with your bike, but it shouldn’t be part of your chain waxing regimen).