Earlier quoted context omitted.
I put money down on a blackjack table, play a hand, win, and cash out with more money than I put in. How is that not an investment?
A better question might be: How is anything an investment? If the stock market is priced efficiently, it is as much a gamble as Bitcoin. The stock market is of course not perfectly efficient, but it is likely extremely efficient relative to the knowledge of your average retail investor. Which means that buying Bitcoin or other cryptos is no more a gamble than any stock market investment with a similar volatility.
so one difference then is that stocks have a justification for their returns given the variance you experience.