Almost everyone drives a manual car, except for a few countries. The vast majority of hill starts I've witnessed as a passenger have been with the handbrake.
We're probably talking the difference here between enthusiasts and non-enthusiast drivers. I learned stick so I could drive sports cars, and I've never felt the need for the handbrake for hill starts because I can just heel/toe. But my wife who knows how to drive stick but only learned because that's what her family had when she learned to drive and doesn't really care about it, always uses the handbrake.
