I agree with most of what you said, but for the last point, I think I can add a different perspective. Because, once I got used to the (pure) functional progra

I agree with most of what you said, but for the last point, I think I can add a different perspective. Because, once I got used to the (pure) functional programming style, I found it more difficult to mix this style with imperative code. It's almost always easier to for example use for example the state monad than writing it with mutation. This is probably quite subjective and it depends what you are used to. For me, I make an exception for tests. E.g. when I mock my key-value database with an in-memory map, I choose a mutable map. But I know that some people prefer FP style even for tests.