Most sniping programs have you enter your true bid. If you enter an artificially high bid, and somebody else has sniped an artificially high bid, one of the two is going to get burned very badly. So badly that they will end up taking a bad feedback, I suspect -- and they will stop doing this strategy.

eBay auctions are longer than a day because many buyers don't go to ebay every day to search, so thus you want to catch, over the course of a week, all the people who go looking for your item, so they will set up a bid or snipe on it. If you are selling a high-demand item where every item gets several bidders, yes, you might was well just do a 1-day auction.

eBay is a sealed bid second price auction. The ability to bid early and disclose your bid confuses people, and they really should not have it if they wanted everybody to be clear, but ignorant bidders like it so they keep it in spite of the confusion it causes. Once you realize eBay is a sealed bid second price auction where some bidders can foolishly reveal their intentions early, you quickly get over any issues about sniping.