Practical use of improper lists in Erlang (perhaps all functional languages)

Question

I\'ve been reading Erlang and OTP in action, and stumbled upon a question with regards to improper lists.

Don’t be tempted to use list cel

Answer 1

OTP stdlib dictionary implementation dict module is using improper lists for key-value pairs. The justification is 2-tuple uses 1 word more memory than 2-element improper list. See efficiency guide for details