Exactly. Making the whole "I don't trust the government to do something smart with my money" argument moot. It has been proposed, voters have seen the proposal, and it has been voted down.
One particular argument would be that there would probably be all sorts of exemptions and subsidies so as to make it ineffective against the largest producers of CO2, which is a version of "I don't trust the government to do something smart with my money," making it not a moot point after all.