What you're proposing just isn't viable or workable at all. What do you expect everyone to do? Say, yes you're right and everyone magically refers to bitcoin exclusively as an currency from now on? Not gonna happen. You can't force people to use or see bitcoin as you do. I also doubt you use bitcoin 100% as a currency. What do you do with your bitcoin? Do you sell or use it to buy things as soon as you get it? Save or hold any of it? You don't have any bitcoin you're holding for a future investment at all?
Can you stop calling Bitcoin an investment?
This damages the cryptocurrency. Bitcoin was not created to become an investment. Before Bitcoin, there were some digital currencies years back, the goal was always to be able to create a (digital) currency free from central banks and governments.
Cypherpunks and other anarcho-capitalists are at the origin of this idea, perhaps 20 or 30 years ago. None were intended to make an investment to be rich quickly.
You won't find in the white paper "investing" mentioned, you won't find any post from Satoshi mentioning it
I disagree with your reasoning. Bitcoin has probably far outgrown satoshis wildest expectations and is bigger than just him and his initial intentions now, but Bitcoin was created as the way money
should work. It's deflationary so that means your money should gain interest over time, not lose value due to inflation as the issuer prints more of it as they please, hence why bitcoin was designed as it is to have a fixed amount and the supply decreases over time. Because of this those who believe in bitcoin see the potential in it for an investment, which it is (in my opinion). It is also a currency and a medium of exchange, but far from perfect as a currency as it stands right now and most people (and likely including you) are seeing the potential for future gains here.
Considering Bitcoin as an investment, this is the reason why we have more and more regulations, G20 summits and others craps, KYC, etc...
The word "Crypto-assets" didn't exist before, why did they create it?
I don't think this is true. You need KYC to use most money services or businesses that transact in money which can be used to launder cash. They created the term crypto assets because that's essentially what they are and need to be classed as something (and usually the government only classes money as something they have issued). We also have absolutely no control over what the government class it as anyway.
Bitcoin could be a lot more accepted and used by now. Why should a merchant agree to be paid in
Bitcoin? He wants money, not a piece of your investment.
This isn't the reason merchants aren't accepting it. Most of them just don't see the need and those that do usually use a payment provider that gives them the fiat instantly. Can you fix the price fluctuations please so it can become a viable currency? Imagine going to a shop to buy some milk and whilst you're in the queue the value has gone up or down x amount? And this is why it currently isn't an ideal currency and is also better as an investment. Without all these people speculating on bitcoin bitcoin probably wouldn't be where it is today. Let people use bitcoin as they see fit, but this is something you, I and everyone else have absolutely no control over and trying to change that would be fruitless.