

If you don’t require it to replace cables it doesn’t need to. For adding some energy to the device while it’s on your desk or nightstand it works perfectly fine.
The efficiency issue is also exaggerated, phones don’t take much power to begin with. Anyone using AC or warm water for convenience is doing much worse in terms of spent energy.
Your Wi-Fi also needs a cable if you want to be pedantic.
The benefit is that there is no overhead involved, in theory you don’t even have to think about charging your phone ever again. When it’s not in use, just leave it on some of the dedicated places around the house and office that provide wireless charging.