What are Gold Laurels rewards?

There are two different types of rewards for each room, and the laurel around the orb showing the reward for that room has a different color for some.

From the Hades Wiki:

Chamber rewards are denoted on their entrance door by a symbol surrounded by either blue or gold laurels. Blue Laurels accompany persistent resources such as Keys, Darkness, or Nectar, that can be used to unlock new weapons, power up the Mirror of Night, or earn Keepsakes. Gold Laurels represent rewards that impact the current run, such as Obols, Boons, Centaur Hearts.

Essentially there are two pools of rewards, the blue laurel ones with resources like keys, darkness and nectar, and the gold laurel ones with god boons, hammers, etc.

This talent gives you a higher chance to get rooms with boons or poms instead of keys or darkness. The effect on hammers is probably negligible as those are limited to two per run anyway.