Earlier quoted context omitted.
If that takes off, aren't we liable to see a rocketing demand for storage, doing to the storage market what PoW does for the graphics card market? And while it may be low energy to run, creating hard drives just to prove you have space seems a less than environmentally friendly activity. It looks just like another proof of waste
The main cost of compute is electricity. The main cost of hard drives is intellectual property (ie. Paying for the R&D, patents and licenses for all the tech inside). It isn't clear that "wasting" intellectual property is in any way bad for the wider economy. In fact, it probably just subsidies storage for the rest of us in the long term.
Instead of electricity consumption the limiting factor will be raw materials to manufacture storage. Likely even worse for the environment given the energy and raw material cost to manufacture storage devices.