Spinward Flow
SOC-14 5K
Probably a simplification to enforce direct line of sight pathing understanding, rather than permitting gravity parabola indirect fire options.But Pulse Lasers are also classified as "Beams" in the general use of the term in T5.
In other words, straight line acceleration.fires it as a beam through a magnetically focused field along the barrel.
So it rapidly transforms in shape from a cylinder/line into being a spheroid/ball after leaving the weapon.The initial beam is approximately 2cm, but it begins to expand immediately.
If you look at the CT Striker weapons catalog, you even find Rapid Fire energy weapons of the plasma and fusion varieties (ala machine gun fire type). They aren't described as being "continuous beam" weapons that you "walk the stream onto the target" like a flamethrower to hose them down with enough plasma to burn through them ... instead they're more like repeating firearms that throw discrete chunks of plasma (fusion optional) at the target like bullets/rounds/shells from a CPR cannon.
Plasma and Fusion Guns therefore have more in common with Pulse Lasers than they do with Beam Lasers (or more specifically, up to and including rapid fire pulse lasers to be extremely clear).