Arthur shook his head in response. It's not that he can't smoke. In the world of magic, when he was young and studying at a magic academy, he also smoked because at that time, almost all the male students did.
There, there is no moral and health education, smoking is naturally not something that is prohibited.
But later, as he progressed further in magic, he realized that the effects of the cigarettes were quite great. The slight deformity on his body caused by the cigarette turned out to make a slight handicap in his magic. He needed a lot of effort to fix it.
This doesn't mean smoking is out of the question for magi, but not before they become Official Magi where mortal things can no longer affect their body.
Harry didn't look like he wanted to be pushy when he saw Arthur refuse. He put the cigarette case back in his pocket.
"By the way, do you like games?" he asked again.
"Yes, I used to, but not now, only when I don't feel like doing anything."
