In languages and libraries that allow FSM and pure functional kernel based designs you can get just as clear logic that is expressible not just to the programmer but also to business personnel. It's counter-intuitive to a certain extent because so much of programming is built around imperative programming but FSM based logic is and will continue to be easier to understand long term because you can trivially visualise it graphically. This ultimately is what a lot of the functional paradigm is built around. Use the mathematical and graphical representations we've used to understand systems for decades. They are well understood and most people can understand them with little to no additional education past what they learned in their business or engineering bachelors degrees.