It won't *kill* battery life but, like any processing of any kind being done, it will use slightly more power though it will probably be negligible in the long run.
For example, WiFi and Angry Birds will likely consume so much more power in comparison it comes down to personal preference as to whether or not you use or do not use this setting. I for one find the effect annoying what with the apps coming at you and going away from you when they become active or close. Things seem so much snappier without the effect on.
But killing your battery simply by having it on? Probably not.