There seem to be a lot of eBayers out there who either do not understand the way automatic bidding works, or keep changing their minds about how much they're willing to pay.
I agree.
Putting in a bid in the closing seconds of an auction gives them less time to react.
For popular items, the vast majority of the "bidding" occurs in the final seconds anyhow -- whether it's manual bids or automatic ones being triggered. For items that only end up getting a bid or two, sniping is more likely to be successful. At least in my limited experience.
Here's another angle. The bid early strategy (assuming it is a reasonable bid) can sometimes "secure" an item because it dissuades lowball bids and can discourage other bidders with a similar price point from entering the auction. (If I see a $15 razor sitting at a $12 bid early on, I'll move on. Not so if it's at $9 with no bids and an hour to go.)