What are advantages of ruled surface in comparision to complete free form?

Dear All,

As far as I know, if a surface is created with between two curves, it calls ruled surface.

And a ruled surface we can draw a line from one base curve to another.

However what is the advantage of ruled surface?

I can't find well, what is better by ruled surface than freely formed double curvature surface.

Can somebody expain me?

Thanks!