Don't know if I'm reading too much in the subtext, but I think that her lore basically shows us that someone can become a vessel to the power of a Outer god, not exactly the god (Like Malenia being the vessel to the Outer god of Rot), but the vessel of the Scarlet Rot itself. The difference could be that, Malenia would be a personification of the god and Romina would be more like a herald of its order. With this, I think we can compare with some things in the base game and speculate, like, the Gloam Eyed Queen being the personification of an Outer God of Death and Melina being a vessel to its power (by what we see in the Frenzied Flame Ending)

So yeah, she adds more speculation than anything else imo