The Bitcoin-Gold Flippening tracks several metrics to compare Gold to Bitcoin (sometimes called "digital gold".) Some of these metrics might put bitcoin on top (in the future); this is the Bitcoin-Gold flippening.

Market Cap

Flip point: $797,771 per bitcoin
Bitcoin: $1,316,480,133,035
Gold: $15,747,056,887,450

Bitcoin's market cap is transparent and can be validated by anyone. For gold, supply estimates vary.
Sources: CoinGecko and World Gold Council reports.

Price Performance

Period Bitcoin Gold
5 year +710.68% +71.68%
3 year +70.37% +23.27%
2 year +196.09% +24.2%
1 year +157.79% +18.64%
YTD +58.02% +12.01%
3 months -8.76% +5.93%
1 month +6.07% -1.54%
1 week -5.74% -3.03%

Annual Supply Growth / Inflation

Bitcoin: 1.70%
Gold: 1.72%

Bitcoin is disinflationary and halves the mining reward every ~4 years. For gold, it depends on how much has been mined and recycled. Theoretically, more new supply means more new demand (buy pressure) is needed to maintain the price.
Sources: Bitcoin code and World Gold Council quarterly reports.