It seems that their all about vibration dampening and nothing else.
The biggest reason I use the short hunting stabilizers, is for balance. Many bows need a little weight in that area, to keep the bow from jumping too much on the shot. There isn't much we can do about reducing torque with a short stabilizer, but it can still be a very useful accessory.
Although none of these add-ons are absolutely necessary, many of us like to tweak our set-ups to get the balance and feel that we prefer. Few people prefer a bow with more vibration, more noise or more recoil on the shot. Some manufacturers are now realizing this and produce bows that are so good out of the box, that these add-ons don't do as much as they will when put on other bows.