Hello HN,
At the risk of sounding completely stupid, why would I want to learn things like Rails, MVC5, Django over something in Javascript/Node?
It seems there are significant advancements being made in the JS world compared to others.
I am a die hard Python lover, but I do not know what do to at this situation.
Do you want to create fantastic 3D graphics and visual effects? Best learn C++ and OpenGL.
Do you want to develop a highly resilient parallel system that can be patched without downtime? Learn Erlang.
Do you want to program an embedded system, or anything where you need to be close to the hardware? Learn C.
Do you want to program mobile apps? Java, Objective-C or Swift.
Do you want to "program" hardware on an FPGA? Verilog.
Do you want to quickly make 3D games or other interactive experiences? Try C# and Unity.
Do you want to advance your own knowledge of programming and computation, even if you don't have a particular platform restriction? Learn any language in a different language family than you're used to, something like Clojure or Haskell or Prolog.
And as you get familiar with other languages, you'll find it's easier each time to pick up the next one.
Your question might better be phrased as, "As a web developer, what are the advantages to learning non-JavaScript-based web frameworks and languages?"
With my limited experience in the web world, the only good, practical answer to this modified question that I can come up with is "diversification". If all your eggs are in one basket when it comes to programming skill, you're very vulnerable to a language or toolset falling out of vogue. I know some Flash developers, for example, who have been absolutely devastated by the happenings of the past several years, because their toolset was far too rooted in Flash. JavaScript is pretty ubiquitous these days, so I doubt something quite that dramatic would happen to it, but it's possible that it could—for example, I can imagine best practices shifting over the next ten or twenty years so that nobody writes Javascript directly anymore, but only languages that compile to it. I'm not saying that will happen, but it's an example of something that could.