The US dollar may be “stable” on a daily basis, but it also loses purchasing power each year without fail.
Bitcoin, thus far, is growing and average of 200% a year.
Each year that goes on, Bitcoin becomes less volitlate, both from a daily average as well as a cost basis.
Since Bitocin has a known fixed supply, you know it won’t be devalued thoruhg inflation. You also know no one can manipulate it the way the dollar, interest rates, banksters, and politics can and does manipulate money, finance, and everything pretty much.
Any store of value starts off volitle and becomes less volitle over time. This is the nature of the market and adoption.
Eventually, Bitcoin won’t be that volitle at all.
Finally, if you are buying BTC for the long run, then why do you care about the price on any given day, week, month or year?
Only the weak and specultiae minded care about price swings.
When you reach the Bitcoin epiphany, you don’t care much about the price, if at all. The onyl price that matters is the price 5 years from now.