Yes Pete, y're quite right with the little lower center of gravity.

But I found out that searching the bar with my feet is easier in rough wave conditions. When I swing my leg over the center-line, my feets are already close to the bar.

Moreover my feet feel more stable on the bar then my knees and standing gives me a sort of mental boost in the tricky situation of the capseize.
When I arrive in the standing position, I know its done, I'm out of trouble.

Finally I was looking for a method which could also be used when I was hurt (maybe twisted something or even broke something). I hope that this trick will give me the best chances in bad unforeseen circumstances.