Board Thread:General Discussion/@comment-43976731-20190930133910/@comment-4010415-20191001231920

The thing is, gathering the four Relics does not grant you a magical wish or god-like power. All it does is bring the God of Light and God of Darkness back to Remnant, and if humans are still fighting each other, the brother gods will wipe the entire planet from existence.

So, judging by Salem's actions and the circumstances, I would assume that Salem actually wants the Relics so she can have Remnant completely destroyed, either because the Grimm infection within her drives her to desire destruction (like Jinn said) or because she's sick of being alive and thinks that, if Remnant gets completely obliterated from existence, she will too and will thus finally be at rest.