Monero could lose it's purchasing power at approximately the same rate as Fiat, I would still use it. It's the most reliable private way to transact online. Yes, you could use Z-Cash, and Mixers, payjoins, coinjoins, etc. too but Monero has the highest anonymity pool, and is more convenient to use, guaranteeing stronger privacy for the general population. That being said Monero hasn't, by most metrics it's been one of the best performed just as good, if not better than Bitcoin recently. Some additional links to look at.

BitInfoCharts

Monero (XMR) statistics - Price, Blocks Count, Difficulty, Hashrate, Value

Monero (XMR) Stats. Transactions count, value, Moneros sent, difficulty, blocks count, network hashrate, market capitalization...

CryptoCurrencyChart

Top 25 crypto coins by return on investment over the past week

Chart and download live crypto currency data like price, market capitalization, supply and trade volume. View in US dollars, euros, pound sterling ...

BTCXMR Bitcoin Monero - Currency Exchange Rate Live Price Chart

Prices for BTCXMR Bitcoin Monero including live quotes, historical charts and news. BTCXMR Bitcoin Monero was last updated by Trading Economics thi...

XMR-USD vs BTC-USD: Performance Charts & Full Comparison

Compare XMR-USD vs BTC-USD performance side-by-side. 1Y return: 47.96% vs -46.39%. Interactive charts, historical returns & key metrics.

😅 but but it’s “private”

Anyone who put $100/ month into Monero over the last 5 years is sitting on 109% return. Then again, people who own Monero don't stack JUST for fiat capital gains.