The belief amongst some is that reddit basically did a rug pull. People could and would buy these crypto points with real money, so reddit likely made money. Odds are it just was not successful outside of niche subreddits, hence:

Its newer Contributor Program, which rewards users with actual money from the Reddit gold and karma they accrue, is one such example. "Part of why we're moving past this product is that we've already launched, or are actively investing in, several products that accomplish what the Community Points program was trying to accomplish, while being easier to adopt and understand," Reddit’s director of consumer and product communications, Tim Rathschmidt, told TechCrunch.

Crypto also hopefully seems to be on the decline, and it's possible Reddit did not want to appear to be behind the times.