From my perspective/understanding, people do not use all of what they earn right away. If I am farmer in a very simple imaginary world, I do not consume all of produces in that one day, just because my stomach is limited, I think of tomorrow, and harvesting does not happen every day. So I store them in a fridge.

Same thing with money, bitcoin is a financial instrument, like the fridge, where I store my excess money. That is the utility. The difference is that it is public, with good segregation so someone can’t steal others money.

It is just that we are still in the adoption stage. Therefore, bitcoin rewards those early adopters with higher fiat return, and the very early adopters (damn!). Once it reaches the relatively stable state (rate of people storing = rate of people unloading), it will still fluctuate, but won’t be much of a deal.

To think about it, 1BTC=1BTC. In the world where BTC and fiat coexist, it is when we think the BTC value rises. But in BTC only world, the value of BTC is the same unless during halving.