Buying something with something else is not a "practical use". Practical use means that you can actually build or make something of value with the product in qu

Buying something with something else is not a "practical use". Practical use means that you can actually build or make something of value with the product in question. The prices for all of these things are almost certainly based on the conversion rate between Bitcoin and the US dollar (or other major currencies). If Bitcoin massively deflates you may be able to still do those things, but it will cost many more Bitcoin: that's the whole point of this discussion. Yes, a $100 has no practical value either. But it's the official tender of the US government, which means that the US government does all of its spending in US dollars. Contracts, paying its employees, etc. The US government (federal, state, and local) spends a significant chunk of US GDP, i.e. a significant chunk of the world's largest economy. A country's currency is understood to be tied to that country's economy and monetary policy. As the economy is larger and the policy decisions are protected from craziness by checks and balance, currencies tend to be volatile only to a certain point in practice. This is even more true when you live in said country: if you live in the US, even if the US dollar is inflating considerably as measured against foreign currencies, the inflation of the dollar on the local economy is generally less. US annual consumer price index inflation has only cracked 10% for the year a handful of times in the last century.