A designed process, very efficient at extracting the maximum price out of a stressful situation. It's a sad state of affairs in Australia right now.
Imagine the same level of stress, but you have to guess what the other buyers are bidding. Do you bid low and hope everybody else does? Bid high, but risk overpaying?
Say an auction closes at 5pm Friday... I bod $500k on Wednesday. Somebody bids $501 Friday 4:50. I bid 502... they 503, right up to the last moment.
And if the site is like some online car auctions, any activity in the last 5 minutes extends the auction by another 5 minutes. So, 504... 505... and on up until somebody walks away.
A home purchase is the largest single thing most people will ever buy. It's going to be emotional, even if the buyer manages to stay calm.