As most of you know in this forum, bitcoin has more advantages over fiat money. fiat money is under the control of governments. With fiat money, we do not have 100% control over our assets. But Bitcoin is not like that and we can freely trade it anywhere in the world without the control of third parties. However, Mexico's third wealthiest man (Ricardo Salinas Pliego) agrees with us and said in a recent interview:
Overall, Bitcoin is definitely better than Fiat Money. But not each other's substitute but complement each other.
The advantage of Bitcoin is that it does not carry any risk of embezzlement by 3rd parties. And it's a very fast medium of exchange. Charge-back is not possible without Fiat Money on the other hand, so Fiat Money is more important in banking transactions. I think Fiat and Bitcoin both are functional at the same time, it is not possible to take over one another.