of course fiat is necessary. because fiat is more or less safer currency comparing with other alternative currencies such as crypto currencies. they are mostly backed by governments and also easy way to make payments.

in the future, will there really be a need for fiat currency? Government can collect taxes in crypto, determine how to allocate it, and spend it in crypto. Ppl can receive salaries and do all commerce using crypto. Loans can be done in crypto. Fundraising can be in crypto. Sure, problems have to be worked out in terms of scalability, does it have to be completely decentralized, etc, the value has to become more stable. But theoretically, is there any reason to have fiat in the future?

It has been established that governments can now do taxation without representation by printing more money (which is a tax on everyone holding the currency), instead of trying to get a bill passed that allows it to increase the tax rate. With crypto this would be no more. All increased taxation would have to pass a vote.

From an economic standpoint, the idea that a country can stimulate its economy by adjusting interest rates is tenuous. There is just as strong an argument that lowering interest rates has caused speculation and bubbles, with calamitous results. In a crypto market economy, capital will flow from where it is needed less to where it is needed more.

Fiat coins are absolutely necessary, for example if you spend with bitcoin and its value changes hourly, it is totally unreasonable. A fiat currency supported by the government is needed at the present time

Well, I think you will start to realize when buying an asset in the real world, we need to use fiat in our own country to solve various matters. even some of the crypto users, will exchange the assets they have for fiat.