Objectively, the money is just a sheet of paper, why? The paper is recognized by the state government to ensure that, so what is the guarantee? that is gold. Which country more and more gold, wealth assets are terrible, that currency is priced compared to other currencies. To understand more about currency you can see the book "War Money" nhé!
Bitcoin is generally accepted by the community and is priced against USD or gold so it's worth it.
In short, every value is converted into gold. But gold has some major disadvantages so new alternatives are available such as money and now Bitcoin.
Bitcoin is not compare with money is simply because money is a paper that you can hold and it has exact mount of value while in bitcoin hs no fix amount and you cannot hold it in your hand.you can only see it in your virtual wallet.