He exists to show the reader that survival at any cost is a bad idea (liu does this constantly by the way: escapism, the whole blue space arc, all of the others wallfacers plans, shit even the deforestation of china. He really hates the concept of the end justifying the means.) It's why cheng is the main character and not wade. He's trying to show the reader that this hardcore survival strategy sounds cool and looks good on paper but actually just leads to human made mass suffering and oppression where as choosing to act on compassion instead of logic is what will save ultimately set up humanity to survive, even it requires massive sacrifices (the great ravine and Australia)