When would someone in a Sculpt Spell’s ‘pocket of safety’ take damage?

According to an Evocation Wizard’s Sculpt Spell class feature, they can create pockets of safety that allow the chosen creatures to:

…automatically succeed on their saving throws against the spell, and they take no damage if they would normally take half damage on a successful save.

I’m reading this to say:

  • If there’s a save, those in these ‘pockets’ automatically make it.
  • If making a save would result in half damage, the ‘pockets’ take no damage.

So, if I’m reading this correctly, why not just say that those in the ‘pockets’ take no damage if there’s a save? Why all the extra words?

When would someone in a Sculpt Spell‘s ‘pocket of safety’ take damage?