Why the damage cap for Thor Rag's special 3

I apologize if this has been discussed before, but I recently pulled a 6 star Thor Ragnarock and as many of you know his special 3 seems somewhat useless unless he is dupped. I guess my question is 2 part:
1 - Is there a benefit to the special 3 that I am missing (primarily if the champ is undupped)
2 - Was there ever a reason stated for the special 3 to have the damage cap. To the best of my knowledge, he is the only champ that has this mechanic. He doesn't seem like a good enough champ to have those kind of drawbacks put in place.
1 - Is there a benefit to the special 3 that I am missing (primarily if the champ is undupped)
2 - Was there ever a reason stated for the special 3 to have the damage cap. To the best of my knowledge, he is the only champ that has this mechanic. He doesn't seem like a good enough champ to have those kind of drawbacks put in place.
6
Comments
His Power Gain ability is overlooked and underrated; especially with Proxima on the team.
If he's not Awakened, his SP3 only inflicts a Shock by itself. With his Sig, he starts placing lots of Shocks, plus Armour breaks, Stuns and bursts of Direct damage.
Awakened, with Hulk/Ghulk alongside, he starts to throw around some pretty decent damage during that phase.