I didn't watch the video. It's weight on the end of the barrel. It's going to dampen vibration. I do find it humorous though that people swear that barrel tuners don't make a rifle more accurate, when it's doing the same thing, when they're just adjustable weight on the end of the barrel.
Of course with suppressors negating the concussion and sound, the psychological benefit of which leads to less flinching and reaction to the shot, and helps the shooter be more precise.