In my experience, Algebraic types alone take some work to get used to using competently. That's just one F# uniqueness and there are others. Learning Elm (a similar language) definitely made me a better engineer, but I really don't think learning F# is the same as learning Python for someone with experience with imperative/OO languages.

I think the reason it sometimes seems like it is that easy is that, as we gain experience with tools, we tend to forget the difficulties we had learning them.

I had difficulties learning OOP, I always preferred a more functional style, despite "consensus" needing 20 years to catch on that functional programming alleviates a lot of the issues we have with OOP.

Learning F# it instantly clicked.

OOP learning issues IMHO are intrinsic to the style, because it's just so seldom helpful in making programming easier.

Design patterns are just a symptom of this issue. That OOP is just a misunderstanding another.

"Real" OOP as practiced in Erlang/Elixir is quite useful.