The argument isn't Purification + Fracture vs Forbidden Chakra.

You should be using Fracture no matter what, the argument is, whether you should use Forbidden Chakra or Purification on the dummies.

The answer is you should use Purification for the dummies, because Monk in 3.0 isn't designed to last 3 minute intervals without Purification or down time. Fracture should be used whether you are using Forbidden Chakra or Purification in a fight (honestly, in most fights you should be using both Purification and Forbidden Chakra).

Throughout the length of a normal fight though, if you are forgoing fractures so that you can get extra Forbidden Chakras, well then that is a DPS nerf. Fracture is too strong a skill to not be using, it not only is very potent, but it helps you squeeze extra ticks out of your demolishes.