SBR can be used effectively against Italy - not like you need it, but it can.
When you’re ready to invade Rome you can SBR before hand to prevent Italy from using its meager remaining income from adding units to its defense.
If you’ve beaten Axis in the Med, and have the SZs stuffed with subs to blockade away Italy’s income, one good SBR run on each Italian factory can shut them down for good, since it can be very difficult for them to come up with even the few IPCs needed to repair it. This can stop Italy from building the inf or two a turn needed to work in conjunction with Germany to trade territory or can-open.