This is a question for Johannes Heidler, who recently welcomed forum questions from anybody who is "really curious about some specific detail".
Why does the Cizin in TRO:3145 have the Battle Computer quirk? Only three other chassis in the entire setting have that quirk canonically, at least to MegaMekLab's knowledge, and they're all quite heavy and incapable of moving quickly. The Cizin is just a fast hovercraft, and I have never seen any fluff suggesting it has sophisticated command equipment.
From a game balance perspective, it's quite questionable: Battle Computer is the only source of +2 Initiative that can't be jammed by ECM, and being on a particularly fast and relatively cheap design seems like an encouragement of cheesy keep-away tactics to preserve that advantage. There's a reason only units in at least the heavy tonnage bracket are allowed that benefit with a Cockpit Command Console, after all.