Real price fluctuations are not about fluctuations in the value of currencies but it is about fluctuations in the prices of goods that we buy using that currency. Ever heard about inflation? That's what I'm talking about here.
Fiat currencies tend to lose purchasing power over time because of inflation and economies going down, and that is even more damaging than a cryptocurrency losing value because a cryptocurrency tends to have the potential to get back to its original price after some time, whereas it is more difficult for a fiat currency to regain its purchasing power very easily. The process is long and you might not even be alive to see it getting changed.
Inflation is one of the biggest reasons why it becomes difficult for a person to manage his livelihood with the limited income they have. If you have always had a fixed income which didn't change much, you must have been doing much better a few years back compared to the current times.
Talking about inflation which is very big if it is calculated annually, but are you going to maintain the same income in a matter of years? are you not investing and so on to sustain your life against inflation? if not then you have to do it, because if I have to talk about inflation by fiat, every year it will definitely decrease the exchange rate, so we compensate for it by investing or getting more income so that life can be maintained in the long run.