For me, heal shifter a must for running boards, unlike a foot peg, your angle point is at your heal when pulling up verse a foot peg angle point center of foot, I`ve seen maney people miss shifts without heal shifter, just my input.
Never used one before. When I picked up my bike the salesman advised to use it and said I would like it. Had my doubts...Works great...would not want ride without it.
I always use the heel, always. I don't really get why you wouldn't. It's a quick, easy natural move. I would, however, like to know the thought, science, ergonomics, reasons for the original heel/toe. I can't think of another brand that uses them. Maybe the Honda Dream ( remember those?).
When I was about 14 years in 1965 my dad bought a used 1962 125cc Yamaha model YA-5 for me to ride.
It was a 'road' model bike and I distinctly remember it having a one piece all metal heel and toe shifter which I promptly removed and put a one piece to shifter in its place.
( Just to add to what Chuck Guitar said above, and yes I do remember the Honda "Dream")
I bought my first dresser in 04. At first I just used the toe shifter. One day I was tinkering on the bike and moved the heel shifter to a lower position. One tooth lower on the spined shaft if I remeber correctly. Been using the heel shifter ever since. Just lift the heel up a little off the floor board and upshift.