PHB Page 102, Sorcerer, Sorcerous Origins, Draconic Bloodline, Elemental Affinity:
Starting at 6th level, when you cast a spell that deals damage of the type associated with your draconic ancestry, add your Charisma modifier to that damage. At the same time, you can spend 1 sorcery point to gain resistance to that damage type for 1 hour.
- The Sorcerer is eligible for Protection from Energy as a 3rd-level spell, requiring 5 Sorcerer class levels to learn as opposed to Elemental Affinity's 6 Sorcerer class levels.
- The only damage type not covered by Protection from Energy but offered by Elemental Affinity is poison damage, and only if Green Dragon ancestry is chosen at the 1st level of Sorcerer.
- A 3rd-level spell slot is worth 5 Sorcery points to recover.
- Metamagic costs Sorcery points, and provides big benefits. Perhaps more benefit than damage resistance, and at an earlier level.
Given the description of Elemental Affinity and the four points above, I have a few intricately related questions:
- Assume that due to resource constraints a character has the choice between using Empowered Spell and Protection from Energy, or Elemental Affinity. How useful is the bonus to elemental spell damage compared to re-rolling the damage dice using Empowered Spell if the only direct-damage elemental spell you have that matches your ancestry is a cantrip? Ex: Fire Bolt, Ray of Frost, Acid Splash, Shocking Grasp, etc.
- Assume that due to resource constraints a character has the choice between using Empowered Spell and Protection from Energy, or Elemental Affinity. How useful is the bonus to elemental spell damage compared to re-rolling the damage dice using Empowered Spell if all of your direct-damage elemental spells match your ancestry? Ex: Red Dragon specializing in Fire spells, Blue Dragon specializing in Lightning spells, etc.
- Assuming you specialize in spells that deal damage matching your ancestry, is it more resource efficient to choose your ancestry based on the bonus spell damage or the benefits of the damage resistance? Use average bonus damage versus average mitigated damage as the criteria for comparison.
- If you choose your ancestry based on the benefits of the damage resistance, is Green Dragon flat-out the best choice because it provides resistance to poison damage? Assume that the campaign environment is organized Adventurer's League play which will use the published adventures. Examples of possible enemies that deal poison damage include Assassins, Basilisks, Ettercaps, Flying Snakes, Giant Centipedes, Giant Poisonous Snakes, Giant Scorpions, Giant Spiders, Giant Toads, Giant Wasps, Giant Wolf Spiders, Green Dragons, Medusas, Nezznar the Black Spider, Phase Spiders, Poisonous Snakes, Scorpions, Spiders, Swarm of Poisonous Snakes, Wyverns, Yuan-Ti Malisons, and Yuan-Ti Purebloods.