I'm going to propose a counter-argument based on an experiment I'm running on myself. I recently started trading stocks because I wanted to expose myself to a different news-sphere. I believe that I will grow and understand more about the world from doing so. Is it addicting? Maybe, but if I learn more about machine learning because I'm running models on stock data, then it doesn't seem too unhealthy to me. Am I going to gamble all my money away on the news cycle and models that I'm developing? Hell no. But then, maybe I haven't had whatever hit I would need to be super addicted to it.

Another hypothesis: the difference is whether you view it as a means or an end. I do not believe that stock trading will ever make me rich. But I believe it is a means to teach me things. Thus it is less addictive.