To be able to not put a number in when you cause or send a player off. As I want to use it for the location on pitch. And it then means it is quicker and less fussing at my watch during the game. Then after the game to be able to edit the caution and input players number. As I will be writing caution down on my card so will have it there for reference. It just means I can be more aware about what is happening on the pitch as I find it hard to type the correct number