Rarity and Power

Options of higher rarities aren't necessarily more powerful than common ones, but they might have unusual capabilities with large ramifications for the campaign setting or the types of narrative moments common in a science fantasy game. For instance, the raise dead spell is uncommon, since Starfinder's default setting assumes that the death of important characters, like the leaders of galactic federations or powerful villains, shouldn't be easily reversed by any common doctor or mystic, only those who have specialized knowledge in these complex fields.