I doubt that those couple of watts per phone will make a dent even if we multiply them by a billion. Wireless charging is 70% efficient in theory, but lets move to 50. So a 17 watthours battery (biggest currently in phones) would waste 17 watthours per charge - equivalent of my any of those - my induction hob, my oven, my electric water heater or my oven working for 30 seconds. Or my gaming PC for that matter.

so 7 billion people, fully charging their phone each day, the phone battery being the biggest one on the market - each year they will waste around 0.17 percent of world electricity production. But since wired charging is also not 100% efficient - if we give it 90% efficiency - this means that we are saving in that case 0.12 percent of world electricity.

I doubt that it will save the planet. The only think it will help is make some people feel righteous with symbolic gestures.