Why would you /haskell/ as opposed to /elixir/, ever?
Other than for teaching the basics, Haskell is just constraining your ability to get things done for no good reason.
Elixir has very pretty and intuitive syntax (unlike Erlang which it compiles too). Elixir is a pure functional language in that variables are immutable, but it provides syntactic sugar to allow variables to be changed (even though they are not). Elixir is moving in the direction of Lisp by allowing lisp-macros to work on its syntax tree. Elixir mirrors Clojure in this respect because Clojure is a lisp that is moving in the direction of being an immutable pattern matching language like ML/Haskell/etc. Clojures immutability allows it to have good concurrency like Elixir/Erlang.
yes, it's a singly linked list
it plays really well with immutability and you can avoid copies most of the time
there's also this magical fusion thing which i don't really know much about
you can also use something like https://hackage.haskell.org/package/vector-0.11.0.0/docs/Data-Vector-Unboxed-Mutable.html