I mean, personally I'm using Elixir more for the language itself than OTP. I have a basic knowledge of OTP now after using the language for 2 years, but FP was my main reason for coming and staying, which for me has been the real fun of it.
Then again, FP for me was not difficult at all, and actually made several of the issues I had with my Ruby code not being expressive/obvious enough, or difficulty in composition, disappear overnight.
> and actually made several of the issues I had with my Ruby code not being expressive/obvious enough, or difficulty in composition, disappear overnight.
I've noticed that pattern-matching and guards just completely eliminate a stupid* amount of boilerplate logic in Ruby code
I fell in love with the language, which is why I kept using it to begin with - working in a functional language is great, and it's very readable and powerful (pattern matching <3).
With that said, I could write basically anything Elixir gives me with Ruby. The real value I get from elixir is the blazingly fast performance of BEAM and the speed at which I can build complex and stable distributed systems with OTP.
The value to me (other than OTP + friends) is not what Elixir gives you, but what it takes away. Not being able to monkey patch things and change mutable state is really freeing. You can do it if you're diligent, of course (I code Java with as many static methods and final, immutable fields as I can and what I know about Ruby, it has things like freeze), but it's hard to never reach for a tool "just this once" if you're in a time crunch.
Then again, FP for me was not difficult at all, and actually made several of the issues I had with my Ruby code not being expressive/obvious enough, or difficulty in composition, disappear overnight.