And another question in which case it may be necessary to set it so as not to raise it any more
I can't think of any practical use case for this unless when sending a payment to a service/merchant that accepts transactions with zero confirmation. They usually reject RBF transactions and do not accept the payment unless after 1 confirmation or more.
Thank you for your comprehensive answer. How do I delete a transaction at all until it is confirmed and if it is RBF?