For the last time, the US dollar is backed by trillions in actual assets AND the governments ability to collect a percentage of our countries GDP every year. It is not based on "belief".
That has got to be the most hilariously tone deaf and ignorant statement I have seen in quite some time. LMAO You believing in the governments "assets" and ability and willingness to stand behind the currency is somehow not a belief? Like I can somehow go to a store and say "No, no sir, you HAVE to give me a loaf of bread for these dollars........the government has office chairs and pens."
And any "currency" that you can walk into a merchant, drop 1 coin worth $60,000, drive out with a car, then that same coin be worth $30,000 the next day, isn't a "currency" at all.
You're example is built on exaggeration to attempt to prop up your point, but in reality that exact situation can and does happen to so called "real" currencies everyday. Or was the Venezuelan Bolivar not a real currency? It was based on the "assets" of the government and their ability to collect a percentage of their GDP.............In that very REAL example the coin worth a $60,000 car was actually worth about $60 the next day.
I went into the gas station last week and dropped $20 on 6.55 gallons of gas. Today my $20 was only worth 6.1 gallons. Next week it will probably be under 6 gallons. The scale is irrelevant, the principle your example illustrates in exaggeration is real (it's called inflation, should learn about it) and no different than what you claim to be a flaw of BC yet is a standard trait of all modern currencies. Your belief in fake monetary policies does not grant a worthless item any value anymore than the BC miner's belief in that currency's "realness" makes it solid.