Cryptocurrency market are very risky, after a green market will be a red market. But because cryptocurrency market raise a lot of newbies came to the industry and if they do not want to risk there are investments funds like
https://defiscale.io/ that invest money in gambling and finance and offer a stable income from investments.
Judging from what Elon discussed, it's not about the green or red market, but the effect that coin mining has on the environment, he prefers to compare which coin is more environmentally friendly in terms of the required electrical power consumption.