Godot 3 actually has some built in DSP effects and send buses: https://godotengine.org/article/godot-30-new-internals-progr...

Regarding visual editing, those tools are of direct interest to any signal processing work(which for games means audio, visual effects, and in some cases asset dependency resolution). They don't work well once your task is too fine-grained. Graphs of finite state are also extremely useful for game AI and concurrently scripted logic, so tools that formalize those concepts and give them visual UI are also commonplace.

In audio work, a FSM is a good starting place to conceptualize processes like key state tracking and envelope triggers. Games have more shifting requirements so the design process of the FSM is given much more emphasis.