I have looked at multiple threads which brought up this topic, but I couldn't find a definitive answer. Even though it might be clear, it might be worth a FAQ or Wiki update. Fatality L1 requires the user to declare a BS Attack using the BS Attribute. Direct Template Weapons require no BS roll to hit. Some DTWs still classified as a BS weapons however, such as the Light Flamethrower. The question is, when declaring an attack with a BS weapon which does not roll to hit, does it still count as "using" its defining attribute?
Personally, I would have liked ALL weapons on a TAG platform to get the boost in damage, but that's unfortunately not how FAT1 works.
@Triumph got it. I would like to add that this also means Fatality L1 won't apply when using those weapons in an Intuitive Attack, as that requires a WIP roll.