I think it depends on what you want the engine to do for you.
If you want to stay on top with the engine that defeats all other engines, then these engine to engine comparisons may be of interest.
But for many of us, what we want is an engine that gives us the most understandable, human analysis to help us understand where we made mistakes in lost games. That may be an entirely different engine, one which has a better "sense" of positional play and tactics, rather than the ability to see a line 25 moves deep which is far beyond human interest or understanding.
And Gull 3 performed worse that's why Gull 2.8 is on list: http://www.computerchess.org.uk/ccrl/4040/cgi/compare_engines.cgi?family=Gull&print=Rating+list&print=Results+table&print=LOS+table&print=Ponder+hit+table&print=Eval+difference+table&print=Comopp+gamenum+table&print=Overlap+table&print=Score+with+common+opponents