Ah, that's not a hard question to answer, honestly! Because, well, sometimes robots can do things humans can't. Like go into space and walk through fire, stuff like that. And they need to be human because they're doing jobs humans would do if they could, so they needs hands and stuff.

Also, I suppose you could say that they make them so that they see it as more than a machine...but then we're getting into philosophical stuff there, and I'm hardly the expert on that.