Those combos have higher meter return rate, which may be necessary considering both Ragna players like to gamble, a lot.
I'm still going with "I like double belial edge so I do it" as first choice though.
In CT, the health gained is based on damage dealt, so you don't want to drag it out.
In CS, it seems that health gained is just constant across any hit (something along the lines of any D hit gains 500 health). This is why 214214D heals so little, and also why regular blood kain combos heals more than it use to.
If you are referring to maho's post, his is a psychic B buster against act pulsr, not a defensive punish B buster I believe. And I am not sure if the punish is legit because nu can backdash moves with 6F start-up (which means regular busters aren't going to work). Maybe act pulsr C is exactly -5F, maybe not.
I saw a tager punish act pulsr C with emerald twice on block (can't remember if it's IB) in a JP tourny recently. You may want to check if that's legit.
Kaqn plays the hazama match-up mostly correct, the recent ones. It's good reference. Nothing else is worth watching.
And I favor A-92's approach more than anyone else. He appears to be the most solid to me.
It may just not work because potentially longer startup on j2a/less untech time on j2a/new tech time calculation.
In any case, I don't think it works for certain hit counts. You are suppose to j2A>jC>gurren>5C or j2A>jC>jC now I believe.
Combo starters that lead into 5CX2, etc:
Easiest are jD, hotaru(>j2C), enma(j2C)
in the corner 2D, jC also works
Situationally enma(counter), yukikaze>kishuu, and from barrier
Corner 6D>6C(full) may also work.