The Haskell Unfolder series of YouTube learning videos is absolutely fantastic. If you feel like bumping into a language you typically do not that often hit during your regular day job, this is for you! Andres Löh backed up by Edsko de Vries from Well-Typed LLP are doing an incredible job producing this material on YouTube. Not to mention other material which is available on YouTube produced by Well-Typed LLP and many others. You can tell Andres has been dealing with the language several decades and is doing incredible job explaining things very clearly indeed.
Haskell is seldom mentioned in job adverts, but it is worth learning – if no other reason than simply for the fun of it! I have been learning the language for the last 6 years and I cannot compare it to any other language.
Having experimented with many languages including F# along with Haskell for several decades, mostly assessing the ergonomics of the tooling such as web servers and ORM implementations, I can say F# is fine and the tooling better than decent. Still, I feel that Haskell has been, is and will be a totally different experience. It is like no other language and is for sure worth learning!
PS. It is not a popular language as such, but I can tell that it is a popular language among those who are hooked by it of whom many have non-Haskell day jobs. You do not need to do it for living as it is extremely rewarding by itself and the community around is really helpful.
I am happy that I did not leave this for a retirement project and I have been privileged to been able to share my genuine interest towards the development of pedagogic approaches to learning functional programming with such pedagogical superstars as Pia Niemelä and Tiina Partanen.
Selma finds chicken treat almost equally rewarding as learning a new programming language.