Imagine you have 3 safes in 3 different locations.
In this example it's a safe at home and two separate safety deposit boxes.
Safe Box 1, 2, 3 respectively.
In a 2of3, with a backup for each seed (6 seeds total) spread across all 3 if one box gets corrupted you lose your monies.
If you abstract the descriptor file away from those safes and keep it in an encrypted cloud or in a 4th box, that adds complexity and potential downside if your heirs need to recover.
In a 3of3, with backups for each - 6 seeds again.
If you spread them correctly:
Box 1 -> Seed A & B
Box 2 -> Seed B & C
Box 3 -> Seed A & C
If any one safe box gets corrupted you can still access your bitcoins, your descriptor file isn't as important if you use standard multisig settings which all the major wallets ascribe to (you should still have the descriptor /config backed up with each seed though)
You know you have done it correctly if you look at the descriptor file & each signer / seed shows a derivation path of: m/48'/0'/0'/2
That's how you know you have the standard settings for your multisig and can recover in the future with no descriptor/config file and also HWW agnostic.
Your heirs will thank you and your security model will be bulletproof.
