+5% NP damage per turn (40% cap).
+100% damage (Saber Wars only).
+5% NP damage per turn (50% cap).
+200% damage (Saber Wars only).
is it worth it
Yes, might be wonderful if your free/cheap to play as you might not have a Dress of Heaven.
If you don't have Dress of Heaven limit broken and you can easily limit break Purely Bloom this one will be better limit broken than Dress of Heaven unbroken in long fights where it will be easily maxed out before you use it on the boss/last wave.