A peremptory challenge also allows attorneys to veto a potential juror on a "hunch". Their use allows attorneys to use their training and experience to dismiss jurors who might say the correct thing but might otherwise harbor prejudices that could infringe the rights of the defendant to a fair trial.
A peremptory challenge results in the exclusion of a potential juror without the need for any reason or explanation - unless the opposing party presents a prima facie argument that this challenge was used to discriminate on the basis of race, ethnicity, or sex.
