The fighting between fiat/crypto fans begin with the born of crypto, sometimes it was silent, sometimes it rages again.. the question was simple whether crypto and fiat can coexist or not, or there should be only one.
Both worlds have their advantages and cons.. Some think that using fiat money will lead to total control, while using crypto will allow to stay anonymous. But I think there would be some kind of symbiosis.. both will coexist in the future and can be used in a balanced manner. I guess it will split in some fields which will highlight pros from fiat or crypto has.
To answer your question, fiat and crypto coexist now, you can use fiat to buy crypto, and vice versa. You can do it in more then one way, wireless or with cash. The question that arises is what FIAT stand for, and what CRYPTO stand for?
"A monetary system is the set of institutions by which a government provides money in a country's economy. Modern monetary systems usually consist of the national treasury, the mint, the central banks and commercial banks."
"Cryptocurrencies use decentralized control as opposed to centralized digital currency and central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain, that serves as a public financial transaction database."
This two definitions can be found on many places, simple google search will show them. Basics!
Now what we know about governments across the world? Banks, central banks, national treasuries? Most of them are corrupted? Most of them works for big corporations? Both of them keep the people in the dark? Rich people are getting richer? Who start wars and who make profit on wars?
What we know about crypto? It`s an internet based medium, it`s leverage blockchain tech to gain decentralization and transparency.
We choose what we are going to support. It`s not the question what will happen with fiat, it`s question for how long it`s going to last, next 5 or 10 years if we are lucky, more then that if we don`t have luck. Cause we need to have better global economy, we need more trust between people of the world, that can only be done with the help of blockchain.