It's more an issue of semantics and differing application of the same sort of assets.
Just to clarify;
Strictly speaking, a sprite is a 2D billboard, often animated, oriented to the camera at all times.
BC's phasers are nested, hardcoded cylinders, textured with the phaser TGA, and coloured in accordance with the harpoint scripts.
The torpedoes are also complex 3D objects, with a sprite core, static textures, and "flares", like petals, that fade in and out of visibility randomly.
The most notable uses of proper animated sprites in BC is actually a mod. NanoFX's explosions are a very evident examples of sprites in BC.
Anyway, I think I'm rambling, I just wanted to clarify why we say the weapons in BC aren't sprites.