The majority of the article was the SC declaring stun guns to be protected "arms" under the 2nd, yet early in the article the author writes:
For the record, I believe my sister should carry a stun gun with as heavy a charge as one can carry legally.
Why carry a .22 (e.g 10,000 volts) if you can carry a .45 (e.g. 250,000 volts); if BOTH fall under the 2nd?
Well. I agree, but being concealable is important. Higher voltage implies larger battery storage, ie size.