Plenty of imperative domain spaces use state machines, gamedev and the like come to mind in particular.
[edit]
For example here is UE3's anim tree[1] editor vs Kismet[2].
[1] https://docs.unrealengine.com/udk/Three/AnimTreeEditorUserGu...
[2] https://docs.unrealengine.com/udk/Three/KismetUserGuide.html