It's nothing to do with multi-sig, at all. 0% related.
I get that splitting the wallet and multi-sig are technically not the same, but isn't the end result exactly the same?
For example, if I want to backup a wallet on paper in different locations, but each one of those prints alone shouldn't be able to spend my coins, I can do either of the following:
1) use your split-wallet approach and if I want to spend the coins, rebuild the wallet with x-of-y prints
2) use multi-sig and if I want to spend the coins, collect x-of-y printed signatures