What is the use case of VR cryptocurrencies?

Could you elaborate on the potential use cases of virtual reality (VR) cryptocurrencies? Are they primarily designed to facilitate transactions within virtual reality environments? Or do they have broader applications that intersect with the real-world economy? I'm particularly interested in understanding how VR cryptocurrencies might enable novel experiences or services within immersive VR platforms. Could they, for instance, facilitate the purchase and sale of virtual assets, or enable secure payments for services rendered in VR? Additionally, are there any specific challenges or limitations that VR cryptocurrencies face in terms of adoption, scalability, or security?