Why do we consider gambling games to be something bad?

[albertnakali]

I have this argument with a friend. He plays at casinos, and I'm always telling him that it's bad, that he's wasting his time, that there's no point in the games he plays, and that, basically, he's not even playing, he's just pressing one button. But he thinks that mobile games like match-three games, which I enjoy, with in-game purchases, aren't that different from slots in essence, just without real money being paid out at the end. I'm not completely convinced, but for some reason, it's hard to come up with a good argument.