It's become a lot more popular in the last few months/years, maybe there's a good reason for that. The English documentation is much better than it used to be, as is the library ecosystem.
I work mostly in Scala, but there's a lot of similarity, and I think the main reason we're seeing it take off now (10 years after originally released) is that the kind of problems where it's really useful are becoming a lot more common. If everything's in the cloud, you need a language that's good at distributed problems. If you need to handle huge volumes of data, you need something more flexible and explicit than traditional languages. If you're using too many layers of technology to understand what they all do, you need a language that can help you keep track of them.
I work mostly in Scala, but there's a lot of similarity, and I think the main reason we're seeing it take off now (10 years after originally released) is that the kind of problems where it's really useful are becoming a lot more common. If everything's in the cloud, you need a language that's good at distributed problems. If you need to handle huge volumes of data, you need something more flexible and explicit than traditional languages. If you're using too many layers of technology to understand what they all do, you need a language that can help you keep track of them.