Can a robot ump determine if a batter swings at a pitch or not? Can a RU add to the determination that a pitcher balks or not? Can a RU call a runner safe or out at the plate? Call a foul ball for a batted ball that doesn't reach the 1B or 3B bag? Call interference for a runner inside the 1B line?
Robo Umps will not eliminate the need for a home plate ump. But they will reduce the volatility of what is called a ball/strike, which is all I really care about.