Bitcoin has the most infrastructure surrounding it. And Bitcoin is the most careful to make life easy for infrastructure providers.

Eth is very challenging to operate securely. Breaking updates are frequent, often with little warning. Bitcoin hasn't changed in many years, and new software updates are optional, and don't require you to write any new code or change how you operate. Most other cryptos suffer from the same challenges.

Eth has more features and flexibility, but for the explicit use case of sovereign money, Bitcoin really stands in a class of its own.