I think the main problem we face is robber will disappear and hacker will increase. Transaction will much easier thanks to that, we not need to afraid losing our real wallet again but we should pay attention to your private key.

I also feel like that, 5-10 years later the people will use crypto as means of payment replacing fiat,
now has not happened because many people who have not known about crypto.

It is imposible for cryptocurrency to replace fiat because it is still not legalized by other countries and for now cryptocurrencies has a low price in the market. It will take a long time for cryptocurrency be replacing fiat because for now not everyone are using and investing in cryptocurrency.

Well you have a good point but i think replacing fiat is okay because crypto is for the future of this world so when crypto completely replace fiat it will be a good news because we can now used our crypto as our currency and that is the main goal of cryptocurrency

Yes crypto is for sure replacing fiat.  Do you not find it odd the world governments are doing nothing to stop this rival to their fiat empire?  This is the new government money.  Your alive during the transition. 

No doubt, at the present moment bitcoin and all the crypto currencies are not being used as currency. People do not understand its importance and facilities very well but developed countries have accepted it already. Their citizens are enjoying purchases and payments in it to some extent. One day in the future, bitcoin will replace paper money.

I think it is not possible to replace the fiat with the cryptocurrency because cryptocurrency is very new to fiat world and it is not recognized by the governments. Still, there are many people who don't have a strong belief on Bitcoin because it is completely digital currency and that to online currency.

I think they are doing nothing about the rise of cryptocurrency because if they are to do something, it will only make people know about bitcoin even more. It's called the Streisand effect (read more) For example, them banning bitcoins or any crypto-related site in your country's ISPs (i.e. making all crypto sites inaccessible) will only raise more attention to the topic. There will be viral articles talking about it and people will ask themselves, "What is this cryptocurrency thing and why does the government doesn't want us to see it?" Hence, they are going to research about it.

People like being involved in something that's a little bit underground. So once crypto sites are banned in your ISP, you're going to use a VPN just to access the crypto sites. A normal individual will feel "cool" or whatever and do a further research about crypto. It's a lot more engaging now that it's not allowed.

tl;dr: They are preventing a phenomenon called the "Streisand effect". (read more)

In my views, cryptocurrency replacing fiat is not too realistic. If we consider how much time we could fully develop cryptocurrency then we could say it would take a decade or more for it to be accomplished.