How does it works.
People sometimes still think that behind the Current money is Gold or such things... simple answer - NO !
if a Country today decide to print more Money, they will do and they build more and more till inflation.
the Current Currency such as Euro, Dollars or Yen are just survive because the People trust in this - if someone gives you 10$ you belive that this are 10$ and the Bank promise to give you for the 10$ also 10$.
on CryptoCurrency there is something behind - Energy ! every coin needs to be mined that means many miners proving all the transactions in the CryptoCurrencys Blockchain Network and Approve that they are Valid.
thats where the Value is comming from - Ethereum is not a Currency for Payments - Ethereum is a Platform where you can run Smart Contracts on. the Currency of Ethererum is Ether ( ETH )