It is an incredibly slippery slope for people to walk out on. It would be incredibly hard for someone to say whether or not they will spiral out of control if they try it and the consequences of becoming heavily addicted are life destroying. It seems like playing Russian roulette and I'm not sure it's a good thing to raise the idea that one can potentially manage it. Also, the person being interviewed could be one of the people that can't control it and will spiral out of control or him saying he manages it well and it's possible to do so could be a facade and he could be trying to do whatever possible to keep his habit alive, but we just don't know. Many people manage it fine for years without anyone knowing until they start their sharp decline towards bottom.