I, very breifly, dabbled in erlang to try and contribute to a blockchain project that use it. It turned out to be a terrible decision because it's not a language with a large and active community and finding people to contribute to the codebase proved difficult for the project. On the surface, erlang made sense for such a project: mainly due to the concurrency primitives and the OTP framework. I still believe erlang is a bad choice for an open source project that deals in difficult problems and depends on lots of eyes and contributors, such as blockchain development.