Makes much more sense, right? In factory it's so much easier to control the environment (flat floors etc.) than to develop the ever next-generation robot that can cope with all situations. Also I don't know what that battery-assembling is a humanoid anyway.
When people say "humanoid robots are designed for human work spaces" 95% of the time they mean the counter/table is at adult human height, the other 5% of the time they mean the robot has to climb stairs.