A 99% purity Elementalist Awakening Serum had an extremely high chance for the user to awaken to powerful or rare elements, like Lightning, Fire, Wind, Metal or Dark.
Or a 99% purity God's Chosen Awakening Serum will almost guarantee that users will receive an attack-type God's Chosen Skill ----------God's Chosen Skills were known to be random and varied, so being able to limit the awakening to just attack skills was already a very valuable thing.
As for the Martial Potential Enhancing Serums, they grant the user a chance to directly manifest a Thaumaturgy right after they use it and become a Professionist.
Such powerful side effects were the main characteristics of a 99% purity Genetic Modification Serum.
But to produce such a single vial of them required not only extremely rare and valuable ingredients but also a certain factor of luck.
It takes a few thousand tries to get a single success.