An iPhone holds 7.45 Watt hours, so if you fully charge it every day it's ~2.8kWh / year. 20% power loss is 560 Wh/year. US electricity use is ~13 MWh per capita per year (let alone total energy use).

I know it sounds wasteful, but it's very important to triage ways to conserve energy, otherwise you end up with things like the awful "unplug your phone chargers" campaign.

I use it for my wireless headphones. It yields convenience. For small batteries, wireless isn't much of a waste. There are other ways to be mindful for the environment. Ways which have bigger impact. Not opting for a wireless charging for environmental reasons is in this case more a matter of "feel good". I get free electricity from the sun as well, and I would save more on electricity by getting a new washing machine (current is 7 years old).