Commercially available defensive duty caliber pistol ammunition designed to defeat soft armor (NiJ IIIa) is a gimmick.
1 – Does the ammunition perform at the same level as HST or Gold Dot on non-armored targets? No.
2 – Does the ammunition perform at the level of HST or Gold Dot after penetrating soft armor? No – mostly shallow penetration ice picking.
3 – Are people faced with soft armored threats where no other areas of opportunity to target are available? No – people aren’t facing 1997 Hollywood bank robber type threats.
Similar to shooting obstructed targets or limited visibility targets, you have to direct shots to the most effective areas presented. If a threat is presented and all you have for a clear shot is the pelvic region, do you engage there or wait for a full silhouette? The ability to assess effectiveness and change your course of action as needed is paramount. Throttle control and precision are needed skills in defensive shooting. Shot placement includes engaging and hitting what is available. You shoot until the threat either changes shape or catches fire.
Until commercial duty caliber pistol caliber armor piercing ammunition is available that mirrors the current premier best performing defensive/duty rounds on both armored or unarmored threats- it is a gimmick for defensive carry. Do yourself a favor and disregard any salesmen, YouTube videos, or personalities that say otherwise. That might give you a clue about their actual relevance beyond seeking money and clicks.