The purpose of this feature as explained here: https://github.com/bitcoin/bitcoin/pull/9662 should be to ensure no mix between hot and cold keys but honestly I don't understand the use case.
What I've used instead is the watch-only deterministic wallet created using a Master Public Key as explained https://bitcoinelectrum.com/creating-a-watch-only-wallet/.

Can anyone explain how to use createwallet "disableprivatekeys" together with fundrawtransaction?