I agree, it's possibly the best course, especially if you have a demanding instructor. One nice thing is that the certification is meaningless, in the sense that it won't open any doors, and the only benefit to the course is the skill and knowledge gained.
Take it to become a better diver, to challenge yourself and grow. I was lucky, I took the course when the sea was choppy so we had a bit of surge, plus my instructor weighed half again what I do. As a result some of the surface rescue excercises were a bit tougher than they might otherwise have been. It was really satisfying to find I could singlehandedly get someone out of the water and onto a pier under those conditions. (Though, with any luck I'll never have to do it for real).