I hate small talk. It’s no surprise for those who know me well. But I do it because I can see it’s social utility.
One must understand, though, that there is only so much social utility in it. Beyond a point, any small talk is a sheer waste of the time for everyone involved in the conversation.
With no phone attached to the charger, it consumes about 0.5 Wh.
When a fully-charged phone is attached to the charger, it consumes about 1 Wh.
When a partially-charged phone is attached to the charger (aka when the phone is charging), it wastes about 4.5 Wh as heat and delivers about 2.5 Wh to the phone.
PS: 1000 Wh costs about 10 pence in the UK and is equivalent to 0.52 kg CO2e.