I would liken it as "digital sexual companionship" in many cases, rather than just porn. That's the value here, for a lot of the same reasons that people would engage with a "traditional" prostitute/escort. It's just cheaper (at first), and less likely to get you arrested or put in dangerous areas.
The article makes mention of AI content potentially coming for this industry, but I believe it's the "GirlfriendGPT" and similar that will be the bigger threat, once they improve.