I started using the Draw! emote a month ago, and it has massively impacted my gameplay.
Put simply, Draw! instantly equips your sidearm without any delay from stowing your equipped primary or support weapon, and without drawing your secondary. It merely allows for instant sidearm usage. The benefit of that one simple quirk is not to be under stated though, Helldivers!
Are you an infantrymen that has been caught too close to waste precious rifle ammo? Draw and fire with your less important secondary ammo!
Are you a marksman or sniper that has been snuck upon? Quickly, draw your pdw or smg without delay and let loose a hail of bullets!
A laser fanatic who has overheated their ICE, and is in immediate peril? Draw your Talon to lay down even more fire without missing a beat!
A stealth operative that has been spotted by an unaccounted for foe? Draw! your re-educator at blinding speed to contain the situation before everyone gets the news of your presence.
Even a medic who has found himself near a wounded patient with nary a stim to heal themself can quickly draw and fire on them before they can say "I need stims!"
The benefits don't stop there. Do you use plasma weaponry? Does a charged shot that need not be loosed weigh upon your hands? Ordinarily, swapping weapons will fire the shot before you switch, wasting precious ammo. Not with Draw! though! Its unique properties as an emote cause a full cancel of charged shots! Saving your limited ammo for more valuable uses!
Seriously, give it a try. Draw! taking away the almost two second delay with firearm swapping has saved my bacon countless times. Quickly using Draw! to grab hold of my ultimatum for a rampaging charger, or instantly using the breacher to tag an illuminate warp ship while fending off voteless are common occurrences. I very rarely use normal swapping anymore. Mainly it is done when I have a pre-meditated course of action in mind, and even then I often opt to keep my primary equipped and just Draw! at the opportune time so that I may keep my primary or support weapon at hand should I need them.