Originally Posted by Eric Montgomery
The thing is, if you fail on a bench attempt you'll most likely be able to control it down to your chest at a reasonable speed until the spotter is able to help you out. If you lose your grip and dump a bench rep (much more common with a suicide grip) the bar is probably going to crash down on your neck or face before the spotter has a chance to react.
This. Yes, I can see why you would think a spotter is useless if you're asking them to catch several hundred pounds in free fall because your grip failed. Not happening, not least because most people just can't react that fast.
Helping you recover when the weight is too much but still under control is a much easier task.