The thing about morality is that it is subjective (granted there is some discourse on that whole topic).
Whether it is immoral - there are societal groups that would consider it immoral. There are also ones who wouldn't find anything wrong with it.
IMO, what ultimately matters is your own morality, and past that, how those you care about would view it (their morality).
Harmful is a whole other topic with a lot of facets though. That I can't help with.
Any gain is a gain. I had to learn this after Bitcoin. Bought a bunch at $100 a pop, sold them later when it hit $250 a pop. This was a day or two before it skyrocketed to ~$1400. Kicked myself then, but came to terms. Now look at them lol.