Well it is steam used to create rotation. But the largest difference I see is the abstraction of fuel. Most engines are designed for a specific fuel.
Throughout the day there are several sources available - yard waste, natural gas, coal, solar, gas/diesel/wvo, electric, and for a few, hydro. Having an engine that can be adapted means versatility.
I often refer to the electron as the "universal power adapter". Well heat is the next most universal power adapter.