Besides the currencies that are supposedly backed by fiat there were also in the past some cryptocurrencies that their creators claimed were backed by gold and all of them failed, if you ask me a cryptocurrency backed by anything is a contradiction, we are trying to be decentralized here and if you want a coin to be backed by something then you will need to trust in a centralized party to keep hold of whatever backs that coin so a cryptocurrency backed by something is not a cryptocurrency in my eyes.