It depends on the circumstances.
Obviously the Axis should scramble if doing so causes British odds of winning to go significantly down.
Still, even if the British are likely to win I would still scramble. This is because the British only have a high chance of winning if they take their carrier as a hit-soaker first. However, if the British do that, some of the fighters from London or elsewhere may not have a place to land, and if they survived the battle they would be destroyed.
On the other hand, if the British start taking combat units first, there’s still a 30-40% chance of the Axis winning that fight.
Overall, scrambling forces the British to make some hard choices at a time when the Italians won’t be able to do much naval damage if the British succeed.