One usage is to prevent government bailout of those big banks in 2008. It’ll help control the deficit for sure. This is macro economics side of the story.
On the micro economics side, on the individual side, it’s the real money. You work 1 month and buy a Bitcoin. 30 years later, your coin will be able to buy the similar labor for 1-2 months. You don’t need interest, you don’t need a financial advisor, you don’t need to take risk to buy stocks. You just know that your coin won’t be devalued by your dear government.
If you save your 1 months of salary in a checking account in USD, you are not sure if it can buy you 1 week of labor 30 years later.
Money is a medium for labor exchange. If your USD loses value in time, it basically favors people who are better connected to Fed or has more brain cells than you.