Hm, definitely misspoke there. I guess I was so caught up in Paulo's angst that I didn't pay attention to her.
Allow me to amend my previous statement: she made for a decent foil for Paulo. However, I do feel like a different character could have served her purpose just as well, if not better. (Silver, Gladion, Bede, etc.) As others have pointed out, maybe they chose her because of her role in USUM's RR plot? (I wonder if she'll end up being to the Villains' Arc what Rosa was to PML....)
I'm also a bit bummed out that Leaf was absent for the duration of the chapter.
Don't read into it too much. In hindsight, I think a part of me is being a spoiled sport following a year of Lillie regularly getting the spotlight (and there's more to come if the Lusamine silhouette in the arc visual is any indication).