>>13051333
The main reasons are:
Poor Economy of Force: A squadron has to fire at the same unit. Because of this, you easily end up risking overkill, especially vs vehicles. (300+ points of Leman Russes taking out a 35-pt Rhino isn't awesome by any means).
-Potentially increased vulnerability. If a nonsquadded vehicle is immobilized, it simply cannot move, though it continue shooting and contributan. A squadded vehicle that gets immobilized is DESTROYED! The crew yells "ABANDON TANK!"
The main reasons to squadron are:
-Torrent: If you want a unit inflict multiple wounds at a time, to threaten other vehicle squads or the specials/sergeants in infantry. (Hydras tend to be best to squad, in units of 2, btw).
-Armor-facing shenanigans: When calculating the armor facing to shoot at against a vehicle squadron, you use the Armor value of the appropriate arc of the *closest* vehicle in a squad. 2 AV 12/10/10 vehicles at an 85 to 90-degree angle to each other, make it a *lot* harder to sidesnipe either vehicle.
-You need to keep moving no matter what. "Free" Extra Armor.