It has 1200/1300 ppm of zinc and phosphorus, and a lot of oils (including the rest of the Mobil 1 lineup) do not.
In fact the Mobil application chart specifically recommends it for flat tappet applications... shruggy

I could run a 10w-30 or 10w-40 with the right amount of ZDDP... looks like Valvoline VR-1 has it too.
The engine was broken in on regular oil + zinc additive, incidentally. Rings are seated, no burning oil.

How would you determine that an engine needed it? work