Is peremptory challenge an important part of trial by jury procedures?

We have acknowledged that that device [of peremptory challenge] occupies "an important position in our trial procedures," Batson, 476 U.S. at 98 [106 S.Ct. at 1724], and has indeed been considered "a necessary part of trial by jury," Swain v. Alabama, 380 U.S. at 219 [85 S.Ct. at 835]. Peremptory challenges, by enabling each side to exclude those jurors it believes will be most partial toward the other side, are a means of "eliminat[ing] extremes of partiality on both sides," ibid., thereby "assuring the selection of a qualified and unbiased jury," Batson, 476 U.S. at 91, 106 S.Ct. at 1720. (emphasized in original)

493 U.S. at 484, 110 S.Ct. at 809.