Other than accepting txns that standard core might not, for any other reason it, to be blunt, seems an odd thing to do.

I guess one use would be, to hide that you've succeeded in stealing someone's BTC, and then there's no chance they could RBF it.

Another point would be that it would delay the transaction.

Since the transaction is going to go public as soon as it ends in a block, I'm wondering what's gained by not distributing your transaction to the network before that happens.