Bitcoin was the first and is still the most famous cryptocurrency. So good news for any cryptocurrency is good news for bitcoin. Most people at this point know that btc exist, they probably don't know what eth is.

Bitcoin as collateral. Given many people got extremely rich off of bitcoin, they can use bitcoin as collateral for altcoins.

Wrapped bitcoin. Bitcoin can be wrapped in a ERC-20 ETH token backed be an actual bitcoin, similar to stablecoins (USDT, USDC, etc.) and traded using smart contracts