As opposed to Fiat currency that has its value debased & inflated away over time through its constant printing via central banks & Governments, Bitcoin is commodity money.
The difference between a security & a commodity is that a security is created by a central authority & ultimately has its value secured by it. In the case of the US Dollar its value is backed by the power of the United States & its military. Although not strictly a security because it doesn’t produce a dividend & does not represent the value of a company it is more like a token. Prior to the “Nixon shock” on 15th August 1971 the US Dollar was a token on gold that could be redeemable as such.
A commodity is common to everyone. There are no barriers to owning it & its value is ultimately derived from its usefulness. The commodity that Bitcoin provides is that of digital data immutability & data sovereignty in the form of Blockchain as there is no blockchain without Bitcoin.
The problem with Fiat currency is that it is ultimately printed & controlled by a single centralised entity that has power over an economy. This means that the price of all stocks, bonds, shares, equities, securities, goods & services are effected directly by the central authority with the power to print money, which can have devastating consequences over peoples lives when the controlling power either acts with criminal intent or is recklessley irresponsible in their actions.
The fact that Fiat currency can be used to purchase Bitcoin means that the central authority with the power to print it could theoretically purchase as much Bitcoin as they desire as the amount of currency they can print is infinite. This ultimately undermines the value of Bitcoin because it means the price can be manipulated by those who simply print the money to purchase it. If this were to happen (which at some point is highly likely due to human nature) the value of Bitcoin could fluctuate wildly and undermine its use as cash.
The only way to prevent Government & central banks from artificially manipulating the price of Bitcoin is to make its price so high that printing Fiat currency to purchase Bitcoin actually undermines the Fiat currency itself. In other words, the amount of Fiat currency that would have to be printed in order to purchase any significant amount of Bitcoin would have such negative consequences on those doing it that it would outweigh any positive benefits they desired to gain.
Due to the fact that national security runs parallel with economic prosperity & printing Fiat currency can be done so cheaply, the likely hood is that central banks & Governments will initially print as much Fiat currency as possible in order to purchase Bitcoin. However, once Bitcoin reaches a price of $1m+ it means $1Bn US Dollars would have to be printed in order to purchase as little as 1000 Bitcoin. $1Bn US Dollars being received by a single central entity for the purpose of purchasing Bitcoin is very unlikely to go unnoticed & therefore questions would be raised about the legitimacy of such a large amount of money & where it came from. This means that those with the desire to accumulate Bitcoin will have to think of alternative ways of doing so, which ultimately leads to the creation of significant sized mining operations or the creation of highly desirable goods & services in business that people are willing to trade in exchange for Bitcoin.
I suspect that Satoshi Nakamoto had foreseen this event unfolding and has purposely designed Bitcoin to undermine & expose those who currently have the central authority & power to simply print as much money as they desire. This is the case for Bitcoin to smash $1m fast!