Before 1971 every government dollar was backed by a store of gold. You could walk into any bank and say "Hey, um, I don't like this dollar bill, and I'd like to exchange it for gold." They'd give you gold. You do that now and they give you funny looks. That's because the USG took the USD off the gold standard in the 1970s. Without the gold standard to keep printing in check the government decided to print and print and print money. The USG/FED now prints 160M USD a day. It's a lot of money, and it leads to a lot of inflation. Essentially the money in your wallet will be purchase fewer goods and service tomorrow than it will today!
Crypto currencies have a range of answers to this, but generally speaking they have a cap on the number of tokens that can be printed and the currency generation is slow. This makes crypto currencies deflationary relative to government fiat dollars. That means that the amount of money in your crypto wallet today will buy more goods and services tomorrow than it will today. This helps give crypto currencies value because if you have the choice of holding your money in a spot guaranteed to lose value or likely to increase in value it's an easy decision.
well in your post you are assuming that crypto will keep going up and that's not a sure thing , especially that you are saying crypto currencies without mentioning names
many crypto currencies will fail in the future as many failed in the past , bitcoin itself isn't a safe bet
still if you are living in a country where the currency is down trending crazy , then yeah you shouldn't hold more than you need of that currency and you should invest your money in any other thing
here the currency went down X10 is 6 years , a good sandwich used to cost around 50 now it's a little bit over 500
so it kinda depends , here we are used to volatility
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