But, you cannot ignore altcoins like Ethereum and exchange coins like BNB. You will need them as long as they have a platform which needs them. You cannot ignore these Altcoins .
what you are missing about ethereum and smart contracts is that it has been useless so far and the only people who are using it are the scammers trying to raise funds out of thin air and the gamblers who are giving up their money to see if they can win some profit.
if "smart contracts" were to become useful and have some real world applications other than what is currently is being used for then it will be used on top of bitcoin as a side chain or a second layer. there currently are at least one project that is doing it called RootStock. the subject is not popular because there has not yet been any real world usage and also these side chains aren't similar pump and dump coins like ether to give profit to be able to produce similar hype.