Why does everyone always compare BTC to USD when it comes to "holding". That's not the only alternative! You're not supposed to hold large amounts of USD over long time periods. It loses value by design. You're supposed to put excess money to more productive uses, e.g. invest it.
No one ever suggests using some S&P500 ETF shares as money even though it also trends up vs the USD. Just like BTC it's also more volatile than money. Unlike BTC it represents something real though.