In the Plastic Memories anime, Giftias are shown just like humans, showing the same attitude and behavior but they aren't humans. They are retrieved after their lifespan is complete. So basically, those are basically humanoids.
If they're not humans, then why aren't they shown with some high intelligence just like other humanoids which are currently present on Earth?
I don't think so. Giftias, however accurate description of human life they may present, they are still just an imitation of how close an Android can be to a human being.
This question can turn out to be philosophical, as we cannot discern what's the true difference between natural and artificial intelligence.
In my opinion, what Giftias can do is all thanks to programming and limited to processing and storage, that still hasn't surpassed human capabilities.
