When you look at things like this in isolation you might think it does nothing, but this is the long fight. Similar to the anti-smoking movement, it took decades of incremental steps to finally get to a tipping point where not smoking became the default accepted point of view.
We are still a decade or two away from the desired result, but I believe this is continuing to shift the default position from "Climate Change is BS", to "it exists, but nothing we can do", to " We can solve this". These things can take a generation to infiltrate the public conscious enough that politicians are forced to act, so as long as we're moving in the right direction, we'll get there eventually.
You analogy is wrong on so many levels.
1. Smoking hurts mostly you and to somewhat lesser degree people that live close to you, in contrast global warming impacts everyone who lives on the planed right now as well as several generations down the line.
2. Stopping smoking has immediate effect. Stopping green house gas emissions even if done completely and abruptly will have delayed impact on global warming as the gases currently in the atmosphere will need time to recede. In addition, the green house effect has a self feeding loop, by increasing water vapor, reducing ice cover, etc. Comparing it to smoking is like comparing hitting the brake on a kids bicycle to hitting the break on a freight train at full speed on a downward slope. (Hint : it will take a lot of time before the train stops).
Your suggestion that we can stop global warming by waiting for the reality to trickle down through the brains of the population of planet earth and take gradual measures is simply ridiculous. By the time this happens it will be too late. I have given up on any hope that effective measures against global warming will be taken in time to preserve the climate to anything resembling the current climate. What we can hope is to prevent a complete catastrophe and adapt to the new climate. Rich countries in high latitudes will fare better. I would really hate to be living around the tropics, especially in arid places like the middle east.