It used to be that doing this and getting movespeed was the same. However, a movement global nerf happened, making IAD useful.
IAD stands for Instant Air Dash. Basically, you jump, and then you IMMEDIATELY dash to the side. Deadlock, like Valve games, work quite nicely if you move in tangent. Be it Shiv's shotgun blasts with vents or shotgun sliding or wall jumping (90 to the direction you wanna go, whatever side to influence to it), strafing with Holiday's jumpad, Celeste movement, vent starfing, even Viscous' slope acceleration (
https://forums.playdeadlock.com/threads/viscous-cube-slope-momentum-bug.107094/), you name it.
Whatever you do, do NOT hold w/s. It's like with TF2/CS/Gmod. You will KILL momentum doing that way.