This is kinda debatable. There is still state in Haskell, regardless of how it's compartmentalized. The implementation of the IO monad for example must rely on

This is kinda debatable. There is still state in Haskell, regardless of how it's compartmentalized. The implementation of the IO monad for example must rely on state to function, because IO is inherently stateful. You may not have to deal with it as much, but under the hood there is still state. And this matters in practice, because sometimes the desired effects of your program are inherently stateful. For example, if you want to have lines of text output to the terminal in a certain order, you have to at least think about state at some level. If Haskell was truly free of any state, this would be impossible to guarantee. What I will agree with though is that it's mostly possible to ignore state in Haskell, and that individual pure functions are truly pure. My point is that those pure functions can't do anything without invoking state at some point.