any position can be worth a try
there are many parts of the body that gravity acts on so if you are upright and gravity is acting on a baby's body in such a way that he/she does not have the strength or freedom to move easily out of or into a position a bit of movement on mom's part can assist I have seen several babies just swing to back anterior with mom in H+K . Also if you look at a contracting uterus it stands out from the body in a similar way that a uterus can hang during hands and knees
I have also felt during the births of 2 of my own children one in which I went from lying to hands and knees to kneeling where i was sitting on my haunches with baby #4 I gave birth in a squat when in a squat and the baby was fully crowned and not moving back, I thought for a second maybe I should move into hands and knees and when I started to move into that position I felt that baby lift off the perineum and decided no I did not want to do all that work to get him down there again so rocked back into the squat. But what I felt was his shoulder and body move more into the open space of my belly/uterus that is not bounded by bony structure maybe even just that slight move was all the help he needed to be born in the next contraction.
I guess what I am saying is if it is working for you then do it and if it isn't serving you then don't. each position has its uses and may be one of the key ones to help a baby be born, I think that it is important to go into labor with a mind set/resolve that you will do and can do anything it takes to birth your baby safely- in water out of water, standing, sitting, squatting , laying, hanging on a swing, on the toilet, leaning into someone or alone, kneeling, dancing, hands and knees ....