I don`t think Fiat Currency will get crashed because the Government are supporting Fiat Currency, so as long as Government supports Fiat currency there will be no reason for fiat to get crashed. But if the Government start transferring their support on cryptos, probably fiat money will get crashed and not be used anymore.
I think governament will never give 1st preference to any cryptocurrency they always give preference to fiat. I don't think in future also they will consider cryptocurrency is legal in their country. But we are hoping it may change in future suppose next generation give preference to this currency then definitely it will affect fiat currency.
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