Claudia Doppioslash discusses some of the useful features of Elm, such as time traveling debugger, immutability, union types, type inference and Functional Reactive Programming.
Claudia Doppioslash is a functional programmer and a game dev. Having learned many languages, she ended up preferring strongly typed functional languages, though she's still a moderately smug LISP weenie. These days she's exploring what FP can do for industrial control systems front-ends, using Erlang and Elm. She writes about Functional Programming on www.lambdacat.com