That's a good question. A difference is that with 1-of-2 you don't need to deal with partially signed transactions, which might be a convenience with less experienced bitcoiners (like my heirs).
Instead of the 1-of-2 multisig, why don't you create a singlesig wallet and give them both the seed?
Essentially,
giving them each: one cosigner + the 2 xpubs
provides no more security than giving them each: one seed phrase of the same wallet
The reason is that in both cases you trust them with the same funds and each one is capable of restoring and emptying the wallet.