Greasing prevents grappling and getting a hold of one's opponent, so it will advantage a pure striker versus a grappler or a rounded opponent.
Marlon Chito Vera is 23-9 with 8 KO, 10 submission, 5 decisions.
By contrast, O'Malley is 18-1 with 12 KO, 1 submission and 5 decision.
So if Chito greased it would basically mean nothing, but if O'Malley greased, he would inhibit somewhat the grappling ability of his opponent Marlon Chito Vera who has the majority of his wins via submission. Although it may not be apparent at first glance, greasing can have quite an effect on striking in an MMA fight.