I've thought this would be a good way to write video games, but most engines don't support the sort of functional programming that would make this pleasant to u

I've thought this would be a good way to write video games, but most engines don't support the sort of functional programming that would make this pleasant to use, so I wind up creating events which solve similar kinds of problems. For games, the primary benefit would be to decouple various game components so you can create and remove them without having to worry about a complex web of dependencies and state. It keeps things declarative, which also helps the web of interdependedness problem of many, overlapping systems.