The most significant and irreplaceable function of the Black Sea Mercenary Corps was to open fire and suppress the enemy whenever Gao Guang and his team were discovered, preventing the enemy from effectively forming a crossfire network.
Without the Black Sea Mercenary Corps, this battle wouldn't have taken place, because modern warfare is largely unrelated to bravery. Forget a handful of people—even thousands of troops would find it impossible to break into a well-formed crossfire.
Therefore, when the Black Sea Mercenary Corps launched a preemptive attack and suppressed the enemy, they had fulfilled their most important task by causing the enemies facing the north to be attacked from both front and rear.