Farra tells Charlie and Max that she wants to buy Atom as a sparring bot for Zeus. However, given her reaction to Max refusing to sell Atom and her reaction to Atom winning the fight against Twin Cities, it seems that this is not her real intention but rather that she is trying to use her money to control the sport (as Max says when he calls her out after the Twin Cities fight). Farra likely saw Atom as a threat to Zeus, as he really had no fighting pattern (Zeus's main feature was to adapt to other bots' patterns) and as a sparring bot he was also able to take a lot of hits and last longer in a fight. Knowing this, Farra tried to buy Atom to sort of move the threat out of the way and control the sport with her money.