I'd say it really depends on what you want to to do in the next months !
Node can be a very productive environment for web APIs and applications (with great frameworks such as Express or Koa and amazing libraries such as PassportJS) and I personally use it this way 95% of my time.
But in its heart lies the event-loop, the streams, the pipes, its functional programming capabilities and all of this makes it a simple and very pleasant way to script, transform, to build algorithms or neural networks!
Plus javascript is becoming a very friendly language as Node and ES6 leveled the browser inconsistencies that turned web developers crazy in the past.