First of all Enum is module in Elixir core code - not library, so topic should be closed. 
ok, but seriously now …
seems is good word here. It would be definitely useful, but also definitely not easy.
Let’s take a look at simplest example Enum.count/1. Do you want to count graphemes, bytes or maybe bites? Enum does not support options in its functions, so it would be hard to write an Enumerable implementation which satisfies everyone. <<…>> syntax have lots of useful types like bits, bytes, utf8 and many more. Such protocol implementation can’t guess based on which type you want to enumerate.
There are probably also some internal reasons for doing that, but I can’t give example here as I’m not a member of lots core discussions. I think that people from Elixir Core Team could say more about it.
