A major reason for developing high level ball handling skill to an autonomous level (Instinctive, without thought) is to liberate the eyes to look up (primary vision parallel with the ground) and maintain as wide a scope of vision as possible. Therefore why the 💀#️⃣🌀💣‼️ are the cones on the ground in so many coaches' skill development drills?
This forces the players to look at the ground in order to perform the drill within the parameters set out by the cones, including not stepping on the cones. This encourages the exact opposite to what the coach wishes to achieve. Instead of their players developing their ball handling skill to look up, they (may) develop their ball handling skill, but forego building good "eyes up" and "soft focus" habits.
If we wish to develop a high percentage of our players to have the ability to 'see the floor' we must design drills that promote this habit. If you must use cones (or markers), consider using the big road cones or another maker that is more equivalent to the height of a player. Alternatively encourage the players to know where they are on the court without the help of a cone and be prepared to accept some variety in where they will change direction on the court. Sure the drill might look a little bit messy to an outside observer but I am confident it will build better habits in your players and this will lead to better performance and team play in the games, when it matters most!