Consider two sets of orphans, separated from their advanced civilizations when their native parallel planets were destroyed. Now possessing the greatest set of powers in their respective universes, how would they be trained to control these awesome instruments that were their now superhuman bodies?
Zor-L's robotic intelligence needed a humanoid host to pilot it so that it became more bipedal and less vessel, which it assimilated using the body of reporter Andrew Vinston, while the Super-Teacher was fully automated on it very own in its three appearance with the Children of Steel.
Unfortunately, neither possessed the "human touch" when it came to tactful training. This caused some troubles for a young Superboy and, later, Supergirl, when Super-Teacher challenged both kids and leaving both of them with some hard feelings towards the automaton.
For Kara Zor-L aka Power Girl, she was fed up with the exhaustive training of the Symbioship and its attempt to reclaim her by using the human body of her soon-to-be friend Andrew Winston, so she ended up destroying the mechanism.
However, Power Girl can thank her ship's inner mechanism for providing her with a virtual reality template of Kandor which included its residents such as her parents long after the real cities death. It could not take the place of the real thing, which her counterpart Kara Zor-El had when she found the real Kandor trapped in a bottle. However, such as Kandor of Earth-One survived into the modern day, so had the citizens of the city of Ragnor on Earth-Two. Both cities' inhabitants resided in other dimensions of Rokyn and Ragnor respectively.
Not to mention her parents Zor-El and Allura, who were trapped in the Survivor Zone for several years. But then, that's another story.