Mechanical triggers are better for those who use the o/u or sxs for hunting like I do. It is not a matter of light loads not initiating the second barrel in my case. But if I spend 3 hours walking and then I flush a grouse, and then the shell in one barrel happens to be faulty and did not fire, I will watch my grouse fly away and will have to hope for another flush sometimes in the day
So I prefer mechanical triggers when it comes to hunting. One shell does not fire and I hear a TICK... I just shoot the other one...
So just to avoid these kind of situations...