This is a very odd weapon, and imho not worth the soul. Before getting into why, i get it's difficult to use and understand. But it has more negative than positive results in the majority of situations, from others experience and my own.
First of all, the ar is high on paper, but the game only shows you the total ar. It has the same split damage problem than friede's great scythe: you will never deal the 3 damage types at once. The true damage is either phys + magic or phys + fire on each hit, and the listed extra fire/magic damage shown in the menu just disappears from the math. The true ar of this weapon comes by removing one of the listed elements, wich would be around -250 ar. (taken from the sum of both blades). The rather low scaling aggravates the situation.
Then comes flat defense and absorption. The reason behind this weapon being good in pvp is because almost nobody levels up vitality and many ppl lacks at least 1 piece of armor for "fashion souls". Those who actually levels up vit and wear full armor has a respectable amount of flat defense, wich is effective against chip damage from weapons with split damage. This weapon suffers greatly against flat defense, as none of it's damage types is high enough to surpass flat defense unless maxed out to +5. Then absorption adds insult to injury to wathever manages to go through flat defense. Unless it's dark damage, wich is the only good element against absorption in this case thanks to it's innate bonus against players.
Second, there is the moveset. In my experience it has the same problem as the drang twin hammers: too slow for a dual weapon and too predictable for anyone who fights against it. Even the r1 has a low startup. You would expect this from heavier weapons that gets hyper armor to compensate for this flaw, but the dancer twinblades has none to speak of except for the weapon art's. Catching someone with a wa combo is just a lottery, regardless of how you play. If you manage to catch someone, you might deal some damage with the combined blades's dps, but don't expect to perform the same tricks twice.
That's about it. Imo, you have a better weapon right at the start of the game and better choices of dual weapons as you progress. Only use this if you re that much into fashion, but don't get your hopes up trying to beat a hard enemy with this.