>> There are plenty of scarce assets defined by no utility except for their scarcity; we call those assets money.

Money doesn't hold value because of its scarcity. Money holds value because of the faith and credit of the entity that backs it.

If a person issued a single unit of currency tomorrow and promptly died, it wouldn't suddenly hold any value simply because it is scarce and guaranteed to remain so.

To put it another way, money's value lies in the fact that it is "legal tender". That status is backed by a powerful organization and people have to trust that organization. When the trust is gone, the value is gone, regardless of how scarce or plentiful the units of money.