Why cryotocurrency is useful?
easy to use and most importantly transparent, because cryptocurrency uses the Blockchain Technology System.
You can read about blockchain technology systems here https://en.wikipedia.org/wiki/Blockchain

What do you like best about cryotocurrency?
the profit given when i invest in cryptocurrency, because when i invest in cryptocurrency i will get a big profit even though the risk of investing in cryptocurrency is also very big.

What makes cryotocurrency better then fiat?
can transact anytime, anywhere and especially we can transact with anyone, then the transactions are also very fast.
besides that cryptocurrency makes it easy for us to invest in ICOs (invest in other countries).