Everyone knows Heroic CHA is the best stat of all. I will atomic wedgie anyone who messes with my Heroic CHA. You have been warned.
H-Cha helps with charming, certain classes wont like that change. Devs also like to regulate sta from a design standpoint.
If this is the only use-case on live, then the DI success chance should be a scaling passive focus AA introduced at the point where CHA for mez/charming no longer really matters to maintain the stat through TLPs.
Focusing on HCHA means people will give you plat when you ask in gen chat. Just try it, just make sure to remind server chat you got like 4K HCHA so they can't refuse.