the only time where a FG is truly advantageous, and not just about preference, is when it's cold enough that the pawls in the freewheel will stick or become frozen.
And that's only during a very cold winter, like -40 degrees, or a very wet and cold winter.
This.
Having a freewheel go kaput out in the woods on a cold night is a pain in the butt. Walking sucks.