I personally think this type of slongan used on crypto is a marketing or promotional terms to move the project token value on a higher value on the crypto market. This is not actually to kill any coin. This kind of language or terms are commonly found these days, it doe not any way detrimental to other coin/tokens. I have also heard of dogecoin killer, the like of Shiba Inu coin as supposedly meant to kill dogecoin, fortunately has boosted the price of Shiba inu coni some weeks ego.
No coin will kill each other, I think it is promotional language or terms.