King B has got a passive skill called 'Cobra reflexes' that increases his attack speed by 30%. This skill can't be learned, and do not untrain your pet as your pet will lose that skill.

King B's damage is comparably lower than other cats because of that particular passive skill. Blizz made it 'balanced' as of patch 2.0.0 when every pet ingame attack speed was normalized to 2.0.

Yes, it is good for PvP against casters, but sucks if you want burst damage.

Btw, may I ask why the first two hotkeys on your hot bar is empty?