Bitcoin - or any cryptocurrency for that matter

Hi everyone
I'm getting more into cryptocurrencies for the last couple of months and I personally see it as the next logical evolutionary step in monetary systems.
Because of that I thought about the consequences it would have if(!) one cryptocurrency with limited supply would be adopted by the whole world (not going to happen anytime soon) as the ultimate step into globalization. Despite the obvious benefits of adopting a cryptocurrency like more safety, anonimity, faster transactions etc. it would make the world and its economy a lot easier more efficient and not that far fetched from reality. (paradoxically because it's a virtual currency) Think of profit the banks achieve through interest for every loan they give any client. What kind of service did the bank provide despite having a lot cash that the can give away? None. But it applies on the other side as well. You give the bank your money in order to get interest on the amount of cash you left them to do their business with. Nonsense. You get money just for owning money. No real value has been generated but still you have more money in your pocket. Wouldn't it make more sense (despite that everyone makes more money going the way of paying and receiving interest) to pay the bank to hold your money and giving you the opportunity to send it anywhere instead of receiving interest?
The problem I want to point out is the fact that interest is not a legit way of generating more value. It's nonsense created by us human beings. An illusion.
Now if the whole world would adopt cryptocurrency. There would be no banks that would have to secure your money because you're able of doing that yourself. The miners who are upholding the system receive cash directly proportional to their effort.
But the interesting part is that there wouldn't be any possibility of giving a loan without actually owning that amount of cash. (The banks give out more loans than they own because of the assumption that their getting paid back) => The economy would be a lot more "realistic" than it is today. (where the amount of cash exceeds the actual real value that should be backing it up) And because of the limited supply of the globally adopted cryptocurrency the value would constantly rise (constant deflation) which would lead to that giving somebody credit would pay by the deflation itself and no kind of interest is needed to make it profitable. => more realistic economy because the deflation is backed by rising demand.
Another interesting sideeffect would be the behaviour of every consumer if all the prices constantly fall (because of the deflation). They (or we) probably would consume a lot more given by the psychological effect it has if prices constantly fall.
Edit: I forgot the most important part! Currency exchange rates would of course would be nonexistent. => More realistic economy. For example look at greece. The debate is about them getting back their own currency instead of Euro in order to save their or mostly the euros economy. But that's nonsense as well. You don't generate acutal real value by currency exchange rates. It's an illusion. They have to generate more real value generally in order to actually save their economy. The point is: you wouldn't be able to manipulate the economy through exchange rates. Which happens a lot.
Now I wanted to ask for your opinion on my thoughts because I tried to discuss this topic with some of my friends and they just seem to not getting it at all what I am trying to tell them and it lead nowhere.
Greets