Comment by mfateev

State machines are useful when the same input/event requires different handling based on the current state. There are not that many applications when this is true. Most of the time only two handlers in each state are needed, success and failure, which are much better modeled through a normal code than an explicit state machine.

At the framework level they might be pretty useful, but they rarely appear at the first version, but as a result of refactoring.