The entire dilemma is a matter of gameplay being an unrealistic representation of what really happens.
You fire a turbolaser at a Star Destroyer, it doesn't get through the armour, therefore it does absolutely nothing at all.
Except armour isn't a number on a statblock, it's a physical part of that Star Destroyer that can be damaged and destroyed, and "nothing" here means "merely damaged the armour a bit".
And if one turbolaser does "absolutely nothing at all", then two dozen will also do absolutely nothing at all", because that's just basic math. Except when one turbolaser merely means some damage to the armour, two dozen turbolasers mean "Boom, no more Star Destroyer" if you can keep the barrage up long enough.