You need to have a good varied amount of brush contact with chinese rubbers to fully maximize its usage but it has its rewards if you have. It is not as good as esn or tenergy rubbers when you are far from the table.
Even with a robot your student will still develop bad techniques if you teach bad techniques. I am not saying you have because i have not seen you coach but you see my point.
1. Too much reliance on arm movement with less hip and torso rotation.
2. Knees are not that bent well.
3. When you do a sidestep to your wide fh from the middle you do a cross over footwork and not a side step which is the result of number 1 and 2.