Plus it's not merely about the length of holding, or about the time-preference. It's also about Bitcoin as new technilogy and its potential to change the world by leading a new surge in a new kind of asset class. The invention of Bitcoin might be something parallel to the invention of the printing press, radio, the telephone, and the internet which changed the world in their own ways, giving new paths of possibilities.
Exactly. If we are talking about Bitcoin, we don't only focus on holding or investing. We also should realize about the potential of Bitcoin as a new technology. Even Satoshi didn't make Bitcoin for investment tool, he made it for an alternative way of digital currency. Sure, we are here to support the change of the world through Bitcoin/crypto. Since there is a country that already makes it as legal tender, it will be easier to achieve the Bitcoin goal. I got your point that it is not only about investment purpose but it is also about Bitcoin adoption in every field of life.
It might be "too risky", but it's a risk that should be taken that would move us forward in my personal opinion.
If we want to succeed, we must deal with the risk. Investing in Bitcoin with high volatility is no doubt quite risky. But if we consider the price growth in the long run, we must be aware that Bitcoin isn't too risky as people think.

I fear that if bitcoins start to be stored, the daily transactions of bitcoins will be reduced to nothing and everyone will save their bitcoins. People seem to be drifting away from the real purpose of Bitcoin's creation.
Is it possible that every one only stores it and leads to no Bitcoin transaction in the exchanges?

I think it is unlikely to happen. There will be always Bitcoin transactions in the exchanges, no every single Bitcoiner keeps it as a long term holding.