No other creature in the fossil record or recorded alive at any point in time can throw like a human and fashion tools to throw like a human with that curved and fragile radius and fragile shoulder held together by ligaments and tendons. It's not just the standing and the walking, the back pain, and the twisting foetus for birthing - the tool use outweighed the disadvantages. Cave guys standing up and bumping in to the stone shelf to grab the good cave drawing soot cursed but kept the verticality.