Imperative is the only Legendary Scout Rifle in Destiny 2.  It is also the only Scout Rifle that gets the following perk: 

• No Distractions - Aiming this weapon for a short period reduces flinch. 

On the surface this seems rather bland, but...

No Distractions was introduced in Season of Opulence on a select few Sniper Rifles. 

Imperative is a high damage, slow shot weapon.  Why that is important, is because missing a shot has a dramatic affect on your effectiveness. The perk No Distractions makes you much more accurate and that means.... you're more effective. 

In PvE the rifle is good at best. It's not meant for close quarters combat and PvE tends to throw a lot of that at you.   Where Imperative really shines is in PvP.

In situations where you can fire at long range, you are Godly.  If you get stuck in medium to short range combat then you're dead... you're dead...you're dead. You would have been better off with a Hand Cannon. That said, if you can find the long range killing channels then this weapon absolutely shines. 3-tap kills are common. 

KackisHD took the weapon into a controlled private match.  He had No Distractions on one version of the weapon and did not have the perk on the other.  He tested both weapons, even explained how Flinch works and came to this conclusion.

Flinch appears to be broken, which means that No Distractions doesn't work. Wow!  

Watch the video: this is cool stuff.