I do agree with some of the things stated in the abstract of this paper and through a quick skim through of everything, but I actually don't do any drugs at the moment (besides coffee if you count that, lol), and I'm also not an alcoholic, though I might get a drink every one or two weeks if I'm going out with friends.
The alcohol, drugs, gambling are relevance only in making people addicted about it. They're both treated as an addiction but in relation with crypto, I don't see any closeness because it is depends on the person. I believe that being addicted to something is a choice not a mistake. For me, I drink alcohol occasionally and I don't do drugs because I'm knowledgeable about the bad effects of it in my health.
I certainly do agree that those especially under 18 should not be allowed to gamble whatsoever, though a lot of countries like the United States do this already.
Gambling is for people who are stressed enough in their work or other things because gambling really can relieve your stress while playing. Some people below 18 yrs. old are not that stress enough because the only thing they are stressed about is their studies and gambling is not the solution for that problem. There are a lot of things for a minor to do, they shouldn't engage in gambling but to explore and enjoy other things.
Crypto and especially crypto trading can be as risky if not exactly as risky if you don't know what you're doing or if you get too cocky. I would not say cryptocurrencies are a solution to gambling addicts since things like leveraged trading exist, but I could see how it might help a select number of people.
That's why this forum is very essential for those who are not knowledgeable enough, so that they can get some idea about crypto trading to avoid being cocky. I think cryptocurrency makes people greedy because they are worrying about their money, that also result from continuously playing and that is considered as addiction. Trading is very different from gambling that's why.