From what I recall, the ecotec that I used, which was for a single trip, it had a system where if you wanted immediate power and you floored the vehicle, it would convert to petrol on its own, when you crossed 120, it converted to petrol on its own and a few other small things.
When a vehicle keeps switching too and fro, the vehicle system remains lubricated and hence the general maintenance issues that are caused due to dry fuel become non existent