When I started buying and selling on Ebay around 2000 I quickly realized that the only way I could actually buy anything was by automatic sniping. The reason is that Ebay has a bastard model: a "conventional" auction with a fixed ending time. I suggested to them long ago that they keep the bidding open until it stops - like a regular auction. With the fixed ending time, you have the equivalent of a sealed-bid auction. A sniping service lets you submit your sealed bid at the moment (almost) that the bids are opened. As another poster pointed out, you [effectively] make your bid and forget about it. No more palpitations or sweaty palms or emotional and reckless disregard of the limit you set yourself - you just look at your email the next morning.
beandk at are-see-enn dot com