3. Additional Rewards for Repeating the Fight
Every time you defeat the Searing Exarch, you can earn:

Omniscient Voidstone
The Voidstone can be added to Path of exile currency your Atlas to increase the tier of your maps. This allows you to progress to higher-tier content with more challenging enemies and bigger rewards.
Higher-Level Crafting Materials
After each fight, you will receive a selection of rare crafting materials and currency items that can help you craft high-level gear.
Exarch-Specific Loot
Each time you defeat the Exarch, you increase the chances of receiving Exarch-themed items, which have their own set of affixes and properties. These can be some of the best items for endgame crafting or even for use in specific builds.
Rare Currency and Items
Expect rare currency items (like Exalted Orbs, Divine Orbs, and Chaos Orbs) to drop more frequently as you increase the difficulty.
Exarch Modifiers
With higher-tier maps and increased difficulty, you may encounter additional Exarch-modified loot, which can have special affixes, increasing the power of cheap Path of exile currency your gear even further.
Increased Loot Quantity and Quality
As you repeat the fight and raise the difficulty, you can also benefit from an increased quantity and quality of loot that drops from bosses and monsters.