My personal impression is that the language infrastructure is not mature enough. As of version 2.0 you cant install Elm on Linux platform from npm because of broken repo link or something (it is known bug but looks like no one cares to fix it). But even you managed to install it, Elm itself does not work behind corporate firewall because it rely on Haskell HTTP library which suck (they fixed this bug in the library but please wait for another Elm release for this to work).

The language looks very interesting and promising, I am very pissed by the fact that I had no chance to try it in our latest project because of those miserable bugs.