Assuming that I understand the way the mod works correctly, it gives +80% additive base damage per unique status effect currently on the target. That being the case, it will be inferior to a maxed Primed Pressure Point until three different status effects have been applied. Why does CO seem to be preferred when it just seems to be not as effective unless you’re also running a status primer of some kind?
Three main reasons:
It’s a cheaper mod. Easier to access, easier to max rank.
Applying three or more status effects is a lot easier than it sounds. A typical melee has impact, puncture, slash, and some kind of modded element. This means CO will beat other options after a few swings. Some enemies will die before CO reaches its full effect, but you didn’t need the extra damage on them anyway. CO is far more effective than Primed Pressure Point against the biggest and strongest enemies, which are where you need the most help.
With a status primer like the Epitaph or Kuva Nukor, CO can produce a far higher damage multiplier than Primed Pressure Point. You can easily get 5+ statuses if you build right, which is a huge damage increase.