Etherium is a better coin since it also has the smart contract feature. There is nothing that you can do with bitcoin but you cant with etherium. So why not all people sell their bitcoin and buy etherium.
No need to mentioned it is better because it has quality and people are attracted to ETH so i would like to say that we should need to use ETH coin because it has a great future and upcoming days it would reach 1000USD.