SourceLook at the M2 money supply in the dollar continues to grow every year and it will weaken the FIAT currency, in the case of FIAT currencies all have the same mechanism and the certainty is that with the increase in supply it will reduce the value of your money, and will you continue to keep your FIAT and let it lose its value, why not just keep your money in bitcoin? Even though you know that Bitcoin has fluctuations, you can still believe that Bitcoin will always fight Inflation and maintain and increase the value of Bitcoin, OR IN OTHER WORDS PRESERVE AND ADD TO YOUR WEALTH IN THE LONG TERM.
Don't let the results of your hard work swallowed by this system.

You can save in Bitcoin if it is convenient for you, you can divide your savings, leave some in fiat, buy some Bitcoin, and send some more to buy assets that can generate passive income. No one forbids you to save everything in Bitcoin if it is more convenient for you, but you need to remember that Bitcoin is a highly volatile asset and in years when there is a bear market, important savings can lose a lot of value, if you are ready for this, then of course you can save in Bitcoin and hold your savings. I am inclined to divide my profits into different assets, diversification is a smart move.