All problem domains that involve declarative programming, such as configuration (Terraform, Kubernetes, Nix, many build systems), dynamic HTML, relational databases, and pretty much anything that is manipulating data in a pipeline fits functional programming like a glove and is hard to get right in a strictly traditionally imperative fashion. As an industry we should stop pretending FP isn't a necessary part of a professional programmer's education and that we can solve the problem by coming up with the umpteenth "we promise it's not FP" abstraction with its own take on fooling developers into writing functional code through an imperative-looking layer full of foot guns that subtly break imperative developer expectations, like React.