I can't come up with any reasonable measure by which Christmas lights use more energy than Bitcoin mining. The reports that suggest this seem to extrapolate US figures across the world, which looks unrealistic. And they're old enough that they don't account for the switch to LEDs.
Even if a billion households had 50 strings of LED lights each and kept them lit 24/7 for all of December, they'd still use less energy than the annual usage of Bitcoin.