This does little except make it so much easier for a man on the run to make a peanut butter and jelly sandwich. See? It has two ends, one for the PB and one for the J. When you've slathered on one condiment, you flip the knife over and... Oh, wait. Then your hand gets all gross. Maybe you kind of twirl it like a drum majorette. No, then you get it all over your pants.
A pox on thee, PB&J knife. You led us on!