Conventional JHP ammunition is better for a number of reasons:
-Penetration: 10"-12" in 10% gelatin as advertised in the video is marginal; 12"-16" is optimal for personal defence.
-Wound area: three .312" projectiles have a combined frontal area of .229 in^2, compared with one 9mm projectile expanding to .60" having a frontal area of .282 in^2
-Range: The lighter, less aerodynamic projectiles will shed velocity more rapidly and pattern very widely at ranges of more than 5m.
-Precision: Multiple projectiles will not allow for precise placement, such as when a head shot is required in a hostage situation.
If you want a multiple projectile weapon, use a shotgun.