"The most challenging to get right are applications that attempt to use blockchains and cryptographic techniques to create a "singleton": a single decentralized trusted AI that some application would rely on for some purpose. These applications have promise, both for functionality and for improving AI safety in a way that avoids the centralization risks associated with more mainstream approaches to that problem. But there are also many ways in which the underlying assumptions could fail; hence, it is worth treading carefully, especially when deploying these applications in high-value and high-risk contexts."