IME pure finite state machines are too limited. E.g. on Android, you have a "go back" stack that you can integrate into a custom state machine, but not into mos

IME pure finite state machines are too limited. E.g. on Android, you have a "go back" stack that you can integrate into a custom state machine, but not into most state machine frameworks. Another difficulty is animated transitions. While transitioning, are you in the start state or the end state? It depends on why you're asking! If you can make it work, a state machine for navigation is great, but it's often not so easy.