Regarding F#'s real world usage, today I came across an end-to-end F# stack, SAFE stack.[0]
It looks very intriguing and I would be interested to know if anyone here has experience with it and has thoughts on it.
Yep, almost all of my side stuff and an ever-increasing proportion of my work stuff is in SAFE. It's actually built on Dustin's Giraffe library, which itself is built on top of Asp.Net Core. Cross platform, great ergonomics due to Giraffe, and I get to share client side/server side domain models, validations, etc due to the shared F# heritage.