Sometimes I bid in bulk for things like PWCC as others have said.
Sometimes I bid because it gives me more visibility, considering I’m watching at least 100 items, it’s easier to keep track of the few open bids.
Sometimes I see an auction for a good item, but it’s flying under the radar. Why not bid to bump up the price a bit and give it more visibility?
Sometimes I bid max right away or close to it early in the auction to detract others from bidding.
Sometimes there is an item I really want, but it is out of price range. If I bid my max early, maybe I’ll get lucky.
Sometimes I just like to watch the world burn…
(Usually never win in those cases)