-You pull them instead of pushing them, because Japanese carpenters used to work on the floor using their own body to brace the work piece
-All wood construction because steel has always been a rare material in a volcanic island without much iron ore veins like Japan
-Most Japanese native woods (pawlonia, cedar) are on the soft side compared to European and American (and from the XIXth century onwards, tropical such as ebony, mahogany) woods. Which is also why they manage to make such thing shavings without tears.
I’ve only ever used a western-style push planet, but intuitively I think I’d have more control with one designed for pulling.
The trend in western planes has been to use speed, the weight and rigidity of iron to cut through wood before it has time to flex, whereas you see those Japanese planes cutting slowly - but again, traditional Japanese wood is softer and less knotty or wavy than the oak or walnut or exotics that are a staple of traditional western woodworking. Look at the Australian woodworking scene for ex., their native wood species are challenging.