Granny bars are the bars you rest your bum on when you're doing stuff at the
mast?
I have them and think they are fantastic. Three points of contact right? Two feet and bum! Leaves two hands to
work.
Mine also provide some protection for my chimney and vents. Coincidentally they also prevent me from increasing my flue height. Which is annoying.
I'm not sure I'd add them if I didn't already have them, but I'm certainly not getting rid of the ones I already have.