Again, not quite. (I swear I'm not just being pedantic for the sake of it!)

You do not need all three seed phrases to recreate a 2-of-3 multi-sig. You need at least two seed phrases or master private keys, but the third share could be a seed phrase, master private key, or master public key. You only need the seed phrase/master private key for the threshold number of shares (2 in this case), but you need one of those or the master public key from every share (3 in this case).

This is important when backing up your multi-sig wallet, since if you have two seed phrases but no information at all from the third share you will not be able to recover the wallet and spend your coins.