[jt2190]

While there’s some truth to “there are programmers obsessed with every language”, functional programming encourages a higher level of correctness, and this can lead to over-analysis and premature optimization if one is not careful. Yes, the additional correctness can be a real benefit, but only if the correctness is correct, and that really depends on the business. If the business comes back every week with “you know, actually we want…” you didn’t get a lot of benefits from the extra analysis.

Couple that with other challenges of running a niche stack in production and it can be quite a burden. Experienced, pragmatic developers will have techniques for managing this even in a functional language, but again, pragmatic may require compromise that doesn’t sit well with the purist.

[snapdaddy]

I acknowledge that there are passionate users of most programming languages, but I also 100% agree that the FP crowd are something different. I feel like most other languages have some nuance at least; if you're writing transpilers or kernel modules then hell yes, Rust makes sense. If, however, you are trying to churn out a web-based store-front, maybe don't look towards Rust.

But with FP, it seems like it is always the answer. And it's even better if your Operating System can be immutable too. And your build scripts. And, even if it take 10 times as long to write, at least we will be confident that it's type safe at the end.