So if you still d not know what actually cryptocurrency is let me tell you cryptocurrency (or “crypto”) is a digital currency that can be used to buy goods and services, but strong cryptography to secure online transactions. that means it is a digital currency with its own value per coin and they work using a technology called a blockchain. Blockchain is a decentralized technology spread across many computers that manage and record transactions. Part of the appeal of this technology is its security.

More than 10,000 different cryptocurrencies are traded publicly, according to CoinMarketCap.com, a market research website. The total value of all cryptocurrencies on July 9, 2021, was more than $1.4 trillion — down from April's high of $2.2 trillion, according to CoinMarketCap. The total value of all bitcoins, the most popular digital currency, was pegged at about $630 billion — down from April's high of $1.2 trillion.

as said there are more than 10k cryptocurrencies out there but some of them are mostly used

Bitcoin-  the first-ever cryptocurrency then came ethereum, theter xrp, dogecoin, and a lot of them

so the question is why are they so popular

1.Supporters see cryptocurrencies such as Bitcoin as the currency of the future and are racing to buy them now, presumably before they become more valuable.

no2- Some supporters like the fact that cryptocurrency removes central banks from managing the money supply since over time these banks tend to reduce the value of money via inflation

3rd one- Some speculators like cryptocurrencies because they’re going up in value and have no interest in the currencies’ long-term acceptance as a way to move money

so as you have seen what all characteristics of cryptocurrencies make it so popular among the people

so will these crypto currencies replace the fiat currencies so let me tell you their possible advantages and concerns regarding this