I bought a Pelacor Deceiver for 10.226 DEC ($0.03 USD).
Just to burn it. I received almost the half of its price back.
Of course I would need to burn much much more cards, not just/only one to actually increase its price. But this is the idea. Burning cards. Currently there are too many Splinterlands cards in circulation, so the supply is too high for the current demand. This is why the average card prices are too low. This is why the card burning is a good idea. If there are less cards, then their prices will be higher.
For example at the time of the writing of this post, there are 757 232 Pelacor Deceiver cards in circulation. I think that even the half of this amount would be too much. Hopefully more people will start burning cards like this.