Not all transactions are created equal. Some transactions are more valuable than others, and there is also value in just maintaining a steady state (holding wealth).
Something that also seems to get lost in the mix frequently is the fact that bitcoin owners themselves are the ones paying for the electricity. The security benefit comes at a cost - manifested as inflation (not just transaction fees) - and that cost is borne by all of the owners of Bitcoin. To that extent, the participants in Bitcoin are actually incentivized to use more efficient systems, because it means the inflation cost of being a participant is lower.
That they don't use cheaper systems indicates (though there are plenty of confounding factors) that they see value in paying the larger cost of holding Bitcoin.
With no transactions, the wealth stored is valueless, like deeds to property on the moon. People store wealth in currencies only because they think they can get it out later. That's in contrast to assets like houses or land, which have use value.
And Bitcoin users are only paying the fraction of the cost paid for energy. But that ignores negative externalities like the pollution that's the subject of the article.
Of course, you need _some_ amount of transactions. But that could theoretically be 500 a year and still adding just as much value as bitcoin today, so long as the transactions were sufficiently significant.
Something that also seems to get lost in the mix frequently is the fact that bitcoin owners themselves are the ones paying for the electricity. The security benefit comes at a cost - manifested as inflation (not just transaction fees) - and that cost is borne by all of the owners of Bitcoin. To that extent, the participants in Bitcoin are actually incentivized to use more efficient systems, because it means the inflation cost of being a participant is lower.
That they don't use cheaper systems indicates (though there are plenty of confounding factors) that they see value in paying the larger cost of holding Bitcoin.