It's worth is best quantified by someone who has had the need for it.
We've had towing insurance with several companies through the years, including Seatow. We went back to Boat U.S. three years ago - since they also insure the boat.
So far we've been lucky, so cannot rate them. But their tow boat stations are widely distributed in our cruising area - an important consideration to factor in your decision.
True Blue . . .
sold the Nauticat