While it's possible to complete almost any task in any language, some languages aren't optimized for some workloads.
JavaScript shines in IO bound tasks and time to market on the server, and of course is the language of the web.
Systems languages shine for high performance and low level OS capabilities.
IMHO python shines for quick script writing with blocking IO for doing things like file processing - I use it as a better bash.
There's a long history of using python for other things like web servers (Django) but I don't think it's very competitive in that space these days with better options like node, go or even elixir.
Very much worth learning different languages to understand the things they are good at and the theories behind their design.
From a practical standpoint, employers like seeing a well rounded developer with experience in more than one language.