As a Destroyer, your main objectives is to hunt down enemy DDs, and secure cap zones, often you dont exactly have to destroy enemy BB directly just by yourself. One BB cannot just push alone when there is a destroyer upfront.
For Random game mode, you should start with USNDD first, you will learn when to engage or not, how to aim, usage with islands, different means to approach cap zone. Also, fewer handicaps because the usable guns, longer smoke, starting from mid tiers, the USN torpedo is better than others and DFAA consumable will save your life from CV.
In short, IJNDD is for the more competitive scenario like Ranked Battles or Clan Battles.
I have played all the destroyers in this game, I can tell the USNDD is the all-around ship here.