It's not totally useless because it contains your transaction history and you might want it not fall into other's hands. Also there could be situations where it's not an option - you want to destroy just a backup, not the wallet.
Yeah I get your point but transactions from an address can still be gotten from explorers excepts that the person needs my address(es) to do so. Also why will someone destroy something which is branded as the best way of keeping a seed phrase back up? To move to another back which will be that?