I also requires additional time to study the demand for that item, how good the condition of the item to new or “Buy Now” ones, your probable competitors who will also bid (based on the bids from the other but similar item), the feasibility of bidding or just buy them now if your study concludes that the difference is just very small.

The above processes requires an effort and thinking. From these data, you can stategized on how much will you bid or just buy them immediately.

http://www.usatoday.com/tech/science/columnist/2006-06-25-physics-of-ebay_x.htm

Another benefit of sniping I do not think mentioned above:

It can help combat shill bidding. The seller or his buddy would not have time to max your bid out and then cancel their’s, leaving you the high bidder, maxed out.

Also, if you decide you no longer want an item, you can just cancel a snipe (maybe up to five minutes before the end of the auction, depending on which service or software you use). If you bid on eBay and then change your mind, you will have to file for a bid retraction. Do that too many times and you can be blocked from bidding on other auctions.