I think there's a lot of disappointment surrounding this champion and I totally get that. However, this is a champion that is truly for players to help their accounts with two important pieces of content that most of us neglect: Sand Devil and Iron Twins. This is especially true for new players. Her Passive will be most useful for these two bosses spefically. Here's why:

Her A3 does sleep first, before Decrease Atk and Decrease Speed. SD needs to be asleep for debuffs to land, this is why it does them separately. Sand devil also does debuffs, which she transfers back (Decrease Acc and Decrease Speed). She also restores Destroyed HP with a really good heal, perfect for Sand Devil. Also Decrease Atk is great for suvivability. Lastly, SD's innate damage reduction is reduced by 10% for each debuff on him. Now why does she do Decrease Speed if she's going to be transfering it back? Because:

Iron Twins requires Decrease Speed to prevent turn meter fill when you buff your team.  Iron Twins also does the following Debuffs: Decrease Atk, Decrease Def and Weaken. Transfering those back increases your team's DPS since she counts as the "Placer" when transferring. So now she's doing 9-12% boost to your team. 

Finally, what is the best debuff for Iron Twins and Sand Devil? Protected Brimstone.  Protected debuffs stay in this case of IT Cleanse. How do you get Protected Brimstone? 5 Star Soul which just happens to be a reward as part of the event. Also, Brimstone might count toward her passive so that's ANOTHER 3% right there.

Again, I fully understand everyone's disappointment, she's certainly no Artak or Wukong. But for players who aren't doing IT and SD, especially new players, this is a great way to help their accounts by getting coins to get Souls to improve their champions and oils to improve their gear