in bjj you have a very wide toolkit of standing techniques: all the takedown techniques of wrestling and judo, plus all the submissions of bjj, PLUS the threat of a guard pull or leg entry at any moment. all these techniques chain very well together, so the more you wrestle the more openings for a sub, and the more you threaten the sub the more openings for wrestling.
a good example is the flying triangle: jumping attacks are unheard of in wrestling, yet in bjj literally any time your opponent has one arm up and one arm down you can jump for a triangle and finish the match. so, if a bjj guy can implement even rudimentary wrestling, say by getting an overhook with wrist control on the far arm, then the flying triangle will be wide open.