I do not believe that bitcoin can completely destroy paper money.  If we have a technology that can accept payment without electricity, then there is still such a possibility.

never, ever forever fiat will remain the official payment currency of the whole world.
and will remain a bitcoin digital currency as an investment and not as a payment currency.
the reason is very easy, where maybe 21.000.000 bitcoin is shared for the whole world.

crypto will not replace fiat and vice versa.
because they have different functions and ways of working, fiat as payment currency and bitcoin as investment assets.

I think Cryptocurrency is very difficult to replace fiat money because Addiction to cryptocurrency is dependent on the Internet, and imagine if the Internet connection in one country is decided, what happens to the financial transactions in that country? Because the Internet bandwidth is controlled by some developed countries, developing countries are particularly vulnerable to countries that hold bandwidth.

Getting into cryptocurrency is more like being open source. You have to be a free mind you cannot keep secrets, for example, suppose you have a bad habit and you have to pay to buy that service or product. Let's take you like smoking and you have to pay with cryptocurrency so everyone around the world will see the transaction you do. This will increase the productivity of the companies by taking the market stat just like a Facebook date but it will reduce your privacy a lot but it will improve the transactions. So you have to decide you need secure payments are less privacy.

I also think that cryptocurrency was created not for the purpose of replacing the currency fiat but that it has its own mission in each and every field. Forming too many coins today is also a great barrier to making crypto very difficult to replace the currency fiat to become the common currency of the world.

It is unlikely that fiat is now considered to be the most liquid, there will not be any coins that can replace them in the present and in the future.

I do not think that's possible. fiat currency is the fundamental of a country that is very important in the eyes of the world and is a symbol of the country's economic power. so the fiat currency will remain and the digital currency will be the option to transact.

Surely this will eventually happen, cryptocurrency can't be fully centralized like fiat money and can't be issued in enormous quantity like fiat money.
Most every state worldwide is living in HUGE debts due to they take money from 3rd parties and promise to return it with %, but it's impossible to return % because this money simply just don't exists, so they have to take new debt to cover the previous, and this goes on and on.
Eventually this system will fail, and many people will suffer worldwide, of course not the bankers who will take money from 3rd parties and will never return them.
Looks like this situation will happen sooner as we all might expect, we are facing history changes in financial industry right now, in my view.

There's no reason to expect that anyone would be able to tell which address belongs to a particular person. Additionally, most people will have their holdings dispersed among hundreds or perhaps thousands of addresses. Lastly, this isn't likely to happen anyway, so it's kind of a moot issue. Crypto is not going to replace fiat, it's just not viable as a currency.