I believe that a seat bag holding the necessary stuff for tube changes and a multi-tool is an essential for me, not an accessory. If I had to choose to remove everything else from my bike and could only keep 1 item, I would choose my bar ends. If my fingers aren't on the brake lever or shifter triggers because they are about to be used, my hands are on the bar ends. I would guess that 80% of my riding is done from the bar ends.