What is wrong with using the referee's decision and applying them based on that? They can have a word, issue a yellow, issue a yellow and advise any further foul will result in a dismissal or send the bugger off. Why does making another option help anything?
Have you considered the potential issue with a player having to warm up again and a higher potential for injuries?
I read it has been used for dissent issues at Sunday league football in England but does not seem to be the reason for expansion into the senior/ professional game.