Shocking Ground not charging Cast on Shock

So I've been using lightning orb and then lightning warp to create shocking ground and apply shocked to groups of enemies. I thought, might as well grab some cast on shock and to my surprise, the shocks from the shocking ground do not charge it at all.

I know it could easily be relatively strong if you counted every application of it at full strength, but it should at least charge it a little.

I think not.
If you read the description of the skill gem then you'll know why.

"Gain 2 energy per power of enemy you shock with HITS from skills."

Shocking ground is not hitting enemies, so no energy indeed.
And for it is so easy to abuse this mechanic and the way they're tuning down all CoX gems, I think this won't change.
Remember there's a unique boot dropping shocking ground constantly, and imagine they allow this to generate energy.

The on hit part makes sense, I missed that. In a hypothetical world where it wasn't limited to hits, shocking ground could be balanced, it's just a matter of how much charge is allowed per mob per second.