When combined with exact inference algorithms, like the iterative CKY (Tsuruoka and Tsujii, 2004), the accuracy will be the same.
if combined with other inexact pruning techniques like beam-pruning (Goodman, 1997) or coarse-to-fine parsing (Charniak et al., 2006), binarization may interact with those pruning methods in a complicated way to affect parsing accuracy.