By the way, I had an interesting thought. Let's imagine that 5 years have passed, for example, the world has accepted cryptocurrency, and let's assume that it has replaced fiat currency. I.e. cryptocurrency has replaced dollars, rupees, yuan and other euros
Let's call it for example BitcoinWorldCoin.
As we understand from classical world economics - a currency with constant deflation is NOT good for the economy. I will not describe why, we can put it in a separate topic, as it requires a lot of explanations. But for interest you can ask your economists, they will confirm this idea.
What is going on? The world is forced to find ways to stabilize the "price" of BitcoinWorldCoin. And what happens ? That's right - BitcoinMicroCoin, becomes unattractive from an investment point of view. And loses its appeal. Yes, as a means of accumulation and savings - it will still be in demand among ordinary people, but large investors will leave it - why do they need something that is stable in price. Another option - Bitcoin World Coin still has an inflationary component, contrary to the essence of Bitcoin World Coin replacement of other currencies.
In both the first and the second scenario investment attractive will be ... GOLD ! 
Your opinion ?
My opinion is that you really don't like your national currency as you constantly phantasise about replacing fiat currencies with cryptocurrencies

I'm not enough sophisticated to be able to say something meaningful to your question.
The first thing I do is to keep separated the money/currency from the investment part, otherwise it becomes too complicated

I'm more interested in the money part, because sound money for a society is more important than good investments.
People - ordinary people - need sound money i.e. a currency that keep its purchasing power over time and don't change it.
Stability is the opposite both of inflation and of deflation.
10 years ago 5 apples costed 1 €
Last year 5 apples costed 1 €
Today 5 apples cost 1 €
Next year 5 apples will cost 1 €
In 10 years 5 apples will cost 1 €
People need "sound" money. Good money. A store of value.
People need stability, predictability.
We are not talking about investments, we are talking about money.
History shows that the the most stable currency is gold.
Gold per se is not an investment, it is money. It becomes an investment only within an unhealthy monetary environment where fiat currencies loose purchasing power.
It's like the Swiss franc: the chf is not an investment, it's a fiat currency, but people around the world - particularly in Europe - "invest" in Swiss francs because their national currencies loose purchasing power.