Actually, whether or not active gathering reduces your GP regen is debatable, depending upon your latency and probably other factors as well. You could gather faster than once every 3 seconds (the GP regen rate) so active gathering was a faster means of regenerating GP (compared to sitting on your duff) prior to this trait. I'm do not know whether active gathering, due to the swing speed, is better or worse than standing GP regen with the trait.

If the trait were for 7 points of GP regen per 3 seconds, or more, then standing around goofing off would be faster regen, but at 6? I don't know.