That's not really how we do things here. If something can withstand the equivalent of several tons of TNT, they're building to city block level. We don't differentiate durability based on the types of damage. Game mechanics is saying that spartans can die from a few bullets without their shields when their armor is bulletproof in the lore. Spartans being able to destroy wraiths in hth is arbitrated and should be treated as canon. If we say that spartans can't actually destroy wraiths because it's "only a gameplay mechanic", then we'll have to downgrade characters such as Doom Slayer or Kiryu because most of their best feats take place during gameplay.