bitcoin is techically more superior then ETH ,yes but the use cases are bigger for etheruem now!
real utility for ETH ARE BIGGER.
ETH: defi, icos, dapps, stable coins.
also the very good liquitity !!
BITCOIN ?
yes you can buy thigns with btc but so you can do with ETH.
It's a question of decentralization and centralization, Cryptocurrency is all about decentralization and anonymity, people embraces Cryptocurrency because of decentralization and anonymity, and this is the biggest edge of Bitcoin and this is one of thing that stopped Ethereum and other coin/token, to surpass Bitcoin supremacy or even up.