A relic is a tier 7 trinket. Its option is what makes it worth carrying, not its numbers.
There are 7 options and each one blunts a particular abyss mutation. Read the mutation that scouting reports for the floor ahead, then bring the mercenary wearing the relic that answers it.
Relics stay out of the warehouse's bulk sell. A relic with no use today often turns out to be the answer on the next floor.