She certainly is a must for most if not all free players, but very few free players have Sherry/Lilia/Olivie/Sybilla and therefore my statement is still accurate (since I said "IF you have a Shrine Plat+ princess, some redundancy is present"). That said, even with them present (I have all 4), her True Damage and Dragon Damage Bonus give her a niche the others lack, so there's good reason to get her even if you pulled one or more of them.