Quick post while I have a minute.

1. Immutability means that the code is easy to reason about, test, and if done properly, much easier to read. You have no surprise hidden mutation of state in random calls. You have no worry about how a variable is going to change as it is called. The program is easy to follow and read.

2. Elixir is built on the EVM/BEAM, if you want to build something for the web, network processing, or as a glue it is unparalleled, you will not have to worry about significantly optimizing your code later as you may need to in any other language. Immutable function programming means you build things up via functions to transform data as it flows through the program, wonderfully simple and expressive without tons of cruft.

3. As an aside, when not to choose Elixir, if you want to learn functional typed programming, something like Haskell will ‘teach’ you better than almost any other language, however OCaml will be the best if you want to write to ‘get stuff done’ (that does not involve massive scale, OCaml has a GIL like Python does (though being fixed later)) at a low level as OCaml is ‘fast’. But as always, for web or scaling, anything on the EVM is pretty hard to beat.

4. Alternatives: There is a growing language on the EVM called alpaca, it is still early and young but it is a typed functional language on the EVM, interoperates with Elixir and all.

5. Notes: LISP/Scheme is not functional, is as about as imperative as it gets by default, and with libraries/macros it becomes anything.

In a way i am asking whether a functional programming language is a better way to program

Not in general, no. Functional programming has its advantages as well as its disadvantages. Listing advantages of functional programming in this forum feels like preaching to the choir, so just to give you a vague idea of where functional programming is just ill-suited, consider dynamic programming algorithms or other algorithms where the most straightforward (and efficient) solution involves continuously modifying an array.

Programming paradigms and languages are tools, not religions. Try them out, gain experience, extend your toolbox, then choose the right tool for the job.

Unless of course you use LFE, Lisp Flavoured Erlang, which is not imperative and behaves like Erlang and Elixir.