The electricity most people use for small electronics pales in comparison to the energy they use for heating and cooling.
The public awareness programs trying to get people to unplug chargers are ridiculous, that money should be spent trying to convince them to move their thermostat 1/2 degree or add insulation.
And please note that I'm not saying that it won't have any impact, I'm saying that the impact it has is so much smaller than other things that it is currently a wasted effort.
Actually there is a big difference between "move their thermostat 1/2 degree or add insulation" and "unplug chargers".
The first either decreases the amount of comfort or costs money (to insulate).
The second saves you money and has a positive impact on the environment.
Also the those awareness programs have side effects:
People now know that stand-by modes in other appliances use energy, thus some of them will take that into account when shopping. Eventually even unplugging some other appliances when not in use. Because of the awareness (and some legislation) companies produce evermore energy efficient devices.
In the long term those programs are not wasted efforts.