I did feel sympathy for the real Lucia to have died in the previous timeline, so saving her means Elena can get her permission to use her appearance and she has access to her father's company! It's a win win situation for both of them!
Even though she is double crossing everyone, Aria has finally realised people like Sarah and Jessie genuinely care about her regardless of if it benefits them. Also the image of her and Asher as allies is the art style at its peak!