Mobile phone chargers without a phone - hype?

So the latest buzz in the media is about being "green" by unplugging
your mobile phone charger when it's not currently charging a phone.

Maybe I'm misunderstanding something, but isn't the only power
consumed due to wire resistance in the primary winding of the
transformer? Seems to me that should be miniscule.

Now phones that don't disconnect the charging circuit when they are
charged, and thus remain hot to the touch, would be a different
story. But I have never encountered a phone with a lithium battery
that did not possess such a cutoff.

So is there any material value to this practice or is it like saving
on gasoline by turning off the radio?

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