Is Darkside worth using?

[pandabearcat]

Is 15% more DPS worth having?

You don't seem to understand the question.

15% dps while you have 0 tp is still 0 damage.

I was wondering that given the scenario where the fight is long enough that you run out of tp consistently, whether the added longevity from not using darkside offsets the 15% damage bonus. If you have to spam unmend/unleash to give yourself tp regen room, it may be better to have darkside off for that part at least.