Update: I had 2 snipes scheduled to fire several hours ago. Of course, being the cheapskate that I am, the bidding went beyond my max snipe, even including the extra bid increments!
The more I think about it, it seems this feature would only appeal to those users who just cannot decide what their true MAX bid is. I found myself working backwards -- I decide what my max is, then subtract the number of bid increments I set in the bid enhancement feature, and then set my "max bid" for that amount! I don't understand why 1 bid increment is not an option in the bid enhancement. I'm MUCH more likely to use the feature to try to avoid losing an auction by ONE bid increment rather than several.