Sniping is a defensive tactic that is the best single defense against shilling sellers. Other bidders have no need and no right to know anything about your bid to be able to bid effectively. Waiting until the last few seconds to enter your one TRUE maximum bid prevents those who would probe your supposedly hidden maximum to set their final bid just above, or worse just below yours, rather than just bidding what they are willing to pay for it.
eBay's auction format is what makes it fair to those in up to 24 timezones with different work/sleep/computer schedules. Anyone can bid what the item is worth to them at any time and anyone can set up with a third party (there are reliable and secure ones which offer free limited use) to submit that bid in the last few seconds (e.g. if they can't be online at that time) to get the defensive benefits of not having one's hidden maximum out there for others (again, including shilling sellers) to probe or otherwise base their bids on.
Inceptions
