I will like to imagine when you said cryptocurrency, you were talking about Bitcoin if not then
1. Not all cryptocurrency are decentralized
2. Some cryptocurrency operates only with the involvement of third party.
3.Not all cryptocurrency have limited supply e.g Ethereum.

You know what
Just change the cryptocurrency to Bitcoin
Because is like you giving the difference between Fiat currency and Bitcoin.

Of course yes I know not all cyptrocurrency are decentralized if you could the thread again you'll see where I listed some cyptrocurrency for example Litecoin, Bitcoin and Euthereum  are decentralized digital currency.So the cyptrocurrency I mentioned in the example are the decentralized cyptrocurrency I was referring to as decentralized.

Firstly it is good to establish that they are both currencies that are mentioned have closely the same functions and an end goal which is an exchange between goods and services. Knowing fully well about this, it is easy to understand the differences of both currencies lies on one advantage or the other, that they poise to improve both of them at a point in time.

1. Unlike cryptocurrencies that operates in an open-source cryptography technology which makes it extremely difficult to be controlled by cabals in the financial institution, the fiat currency is absolute issued and controlled the government and in the hands of the cabals in the financial institution. To a large extent these are the guys that move the market

2. Cryptocurrencies can also be refers to as the much needed alternative that was a monumental thought by the founder Satoshi to bring about freedom. Now, that we have the opportunity to own our funds.

Aside the abovementioned, most of the things are secondary

First, you are incorrect in claiming that not all cryptocurrencies are decentralized, because all of the cryptocurrencies listed here, including Dcash and CNY, are centralized coins.

So fiat currency and cryptocurrency cannot be the same thing since cryptocurrency has a lot of opportunities, whereas fiat currency does not, in my opinion and perspective on the topic, which I honestly understand. Because, in terms of security, cryptocurrency is prone to technical exploits and is based on encryption, whereas fiat is safeguarded by government rules and infrastructure.

In my own opinion, it is good to see that in this era we are presented with a good option...one that can have a big impact on people's financial future and that is cryptocurrency. However, this is not a perfect thing most especially in the applications of it in the real world well just like the fiat currency under the control of the entity or the government behind it. As for fiat currency, you don't have to know many things before you can use it all because it is physical you bring in the paper money to any store, to the bank and you don't need to bring anything else to make a transaction. Compare that to cryptocurrency, here you must have some basic knowledge with technology behind it otherwise you run the risk of losing your coins or tokens.

Each has its pros and cons, we can say that cryptocurrencies are superior to fiat currencies, but that does not mean that cryptocurrencies have no disadvantages and are 100% perfect.

In your example, it's true that crypto would be useless if we didn't have cell phones, computers, or internet, but fiat would work. But if in case, you move far and need to carry a large amount of money like millions of dollars, or the country is at war and you need to move your assets. Or you need to transfer money abroad...it's clear that cryptocurrencies are completely superior to fiat currencies and much more convenient.

Furthermore, the goal of the created cryptocurrency is not to completely replace fiat, and it is only an alternative. Both will coexist and not replace each other.

Op, to me bitcoin is not a cryptocurrency as I see it, this posses some quality that most crypto does not have, starting from security, identity being personal and decentralization itself, that's why till tomorrow some people see altcoin and shitcoin as a scam, Bitcoin exist in a solid foundation but other crypto currency don't, they only digital asset that's well know and recognised by many is bitcoin, despite the volatile nature of this currency, it controls other cryptocurrency, it also has value than them, calling Bitcoin crypto is not ideal to me, I prefer you call calling it digital asset.

Fiat doesn't take only physical form, it could also be online or take the form of CBDCs. You can decide not to use physical fiat and can still engage in financial transactions without restrictions.

This your point is arguable because if not for the congestion of the Bitcoin mempool by Ordinals, the transaction fees is lower than fiat.

Bitcoin is a cryptocurrency but it is unique this why any coin beside Bitcoin are called altcoin. Many developers have tried to introduce cryptocurrencies that will compete with Bitcoin but none of them are close to its class.

Some of what you have mentioned as similarities and differences can actually be only applied to bitcoin a lot of the replies have already mentioned what you should change but i would like to add that the main difference between fiat and cryptocurrencies is that fiat is issued by the government meanwhile cryptocurrencies are operating on a technology called blockchain

Maybe you should start introducing bitcoin first and its differences with fiat because almost all other cryptocurrencies are just derived from bitcoin itself other cryptocurrencies aside from bitcoin are already called altcoins and even though a lot of these cryptocurrencies are like i said derived from bitcoin, some of them still have some distinct features like how some altcoins are not decentralized and many more

I've done some correction in the thread, thank you all the correction.