Doesn't seem "lazy" to me. Keep in mind that the current-carrying capacity of a given cable is dependent on both the wire gauge and the length. So even if you intend to upgrade the battery cable capacity (by going to a larger gauge cable), the section to the frame ground point is probably more than adequate wire-size-wise. The voltage drop difference of 4GA vs 0GA over 1 foot is near-zero; over 10+ feet though and the fatter cable shows promise.
You could then decide if the section along the PPF needs upgrading by itself. Possibility would include running directly to the Starter/alternator/etc; certainly the connection to the PPF works, but copper or brass to aluminum is not ideal as far as electrical connections go (aluminum oxide is a poor conductor and is the reason aluminum house wiring no longer meets building codes). Would be cheaper (large gauge battery terminals + ring terminal costs more $$$) and without any capacity drawback.
In any case the decision re: OEM or alternates here should be made with an overall plan in mind (upgrades could be done later).