Multisig gives two or more people access to sign a transaction and not in the case of securing the wallet phrase, because each cosigner has a copy of the keys, so if you only want to device a means of saving your keys or seed phrase, you may not have to use a multisig wallet, instead use a standard wallet and store your keys separately

Storing seeds alternatively only helps to recover your seeds in case you lose access to one, you have a backup to use and fall back on, which is different from two cosigner signing a transaction.