i still think theres a place for guided energy weapons, weather they be secondary or primary. the point is you have a weapon that doesn't need ammo of any kind, yet can still actively track a target. i believe tachyon had some weapons like that. of course energy usage for secondaries would blur the line further. on the other side nukemod has a high velocity, rapid firing rocket launcher that is a primary weapon. it doesn't home but it acts much like a missile, it uses ammo and energy simultaneously. im also somewhat loosely interested in a battletech mod where lines would get blurred even further, since weapons are neither primary nor secondary.