In addition to TT I also play badminton, and did so before restarting my TT career. Since I already hade indoor (=badminton) shoes, I naturally use them during my TT sessions aswell.
My question is, in what ways do TT specific shoes differ compared to other indoor shoes, developed for badminton, hand ball, volley ball, floor ball etc?
One of my club mates said the main difference is that TT shoes have stickier soles compared to other indoor shoes. True?
That can be gripper yes, but it depends on the shoe. Your need for the gripper sole also depends largely on the surfaces you play on.
I play at several suburban clubs regularly here in my home city of Perth, as well as at the main TTWA centre. The suburban clubs usually play at indoor basketball / netball / volleyball stadiums, which means sprung wooden floors. On these surfaces you need and want a shoe with good grip and good lateral support for sideways movement.
At the TTWA centre however they use proper ITTF authorised flooring, which can be naturally pretty grippy stuff. Court 1 there has brand new flooring on it with very high grip indeed -- if I use my regular indoor court shoes on that stuff, I can risk falling over or twisting my ankle if I don't really lift my feet fully off the floor fully with my footwork.
Extra grippy shoes + extra grippy floor = no room for "squeaky" footwork or dragging your feet during a pivot or step around. The second your shoe touches the ground even partially or lightly, it grips like glue. If your body weight is still moving sideways or rotating at that point, your feet won't accommodate the movement by sliding across the floor. They just instantly grip the flooring in vice-like fashion, and you end up rolling your ankle (ESPECIALLY if your over 6ft tall like I am, and it's harder for you to maintain the super wide stance some coaches seem to favor. On these kind of surfaces, you don't use slide-ways basketball like moments, you really need to lift those feet! ... You have to lift your feet so much it can almost feel like you're using a skipping rope, or doing traditional boxing footwork.
Long story short, have one super grippy pair for wood floors, and another slightly less grippy pair for proper TT flooring. Your ankles and knees will thank you for it.