Years ago, car manufactures wanted to get 200K on catalyst converters, HOWEVEVR this was not achievable with zinc in the engine oils, (ZINC CLOGS CONVERTERS OVER TIME) that's why most oils use other additives other than zinc. If you purchase (for instance) Mobil 1 High mileage, it contains zinc, so do other high end synthetic oils. I use the ZDDP additive in all my Turbo 3.8 V6's, its truly worth the coin for the added protection. I use the High mileage Mobil 1 AND the zinc additive, best of both worlds!
I belong to another car group that includes an oil engineer that explained that adding ZDDP additives can cause more harm than good as too much is just as bad as too little. I accept his advice over others and that is to buy an oil with a good additive package such as Rotella, Brad Penn, Valvoline VR or other racing oils.
Note that you only need the additives on engines with flat tappet camshafts. Roller cams do not need the additives.
I run Brad Penn in my one vehicle that has a flat tappet camshaft.