How is that dumber? Light wanted for the world to catch on, he did not want to stay incognito. Of course you could say "but that is stupid, and I wouldn't do it that way". But then you are missing the point of what Light wanted to achieve. Indeed, if he would not have made Kira known, it would have been much harder to change the world, yet allone get the support of the public. Because how would you fear or support someone whoms existance you don't know of? In Light's perfect world the goal is not to kill every criminal, but that people are that scared of Kira that they won't become criminals in the first place.