Newb Q About Plain Rifle

Hi there, some basic poking around has turned up some answers regarding the difference between weapons, but this sort of thing still leaves me wondering.
Why does the plain 'Rifle', with Moderate Damage and Short recharge, cost more than Moderate-Heavy, No recharge Null-Ray variety?
While a gun with a higher base damage having a form of advantage I can grasp, or just a faster attack rate (It's why I'm not bothering to ask about the X-ray Laser compared to Plain Rifle), why would a weapon that is only better in both damage and speed cost less? Is the weapons list not a full listing of weapon properties, like some weird accuracy bonus? Or is the Rifle just a sad little piece of useless?
Why does the plain 'Rifle', with Moderate Damage and Short recharge, cost more than Moderate-Heavy, No recharge Null-Ray variety?
While a gun with a higher base damage having a form of advantage I can grasp, or just a faster attack rate (It's why I'm not bothering to ask about the X-ray Laser compared to Plain Rifle), why would a weapon that is only better in both damage and speed cost less? Is the weapons list not a full listing of weapon properties, like some weird accuracy bonus? Or is the Rifle just a sad little piece of useless?