Just FUD. I've been on a big team writing a webapp used by hundreds of thousands each day. While it's not necessarily my own first choice, it was great and the least error prone piece of software I've written in my career.
Elm's value proposition is mostly being a functional language with an opinionated MVU library baked in, so you can reproduce that value with a better functional language and selecting a similar MVU library in that other language, which means it should never actually cross the value bar above the risk it brings if you need a browser feature it doesn't support and actively prevents you from accessing.
Production is not some place you're supposed to cowboy code, but instead have a reasonable expectation that you will be able to continue supporting it for as many years as it operates, and it's impossible for anyone to responsibly use technology with known limitations that have bitten other real engineering teams that they can find zero workarounds for.
If you don't consider that an impossibility for a production environment, then I certainly wouldn't want to work with you on a team with production responsibilities.
If you want to rely on them for every possible future requirement or rather want to pick another tool is another question :D
Anyways, just building the compiler without that check was also not that hard.
To me it looks more like the elm-haters are out in force and the Elm users don't participate anymore on this site.
Many hateful comments here below a historic post prompted me to create a new account after a detox phase of >10 years.
So far I try to correct a false statement in the (as of writing this) top comment [1] or add a more neutral view [2]. And maybe I will add more of my personal opinion in the future - or participate in other interesting topics depending on my mood.
[1]: https://news.ycombinator.com/item?id=39555542 [2]: https://news.ycombinator.com/item?id=39556395