User blog comment:VedranTheII/Pretentious Diaries 2: What tricks would you teach your Aura?/@comment-10380701-20150718080559/@comment-10380701-20150718112353

Dust by default can be used offensively and defensively. Though Ice Dust appears to be the best for that. (Would YOU rather use a wall of electricity to defend yourself? XD)

With regards to lightning dust, it CAN be used to attack. But it can also be used to buff one's speed up.

Remember, Dust is not a Mana Crystal to cast spells and shit, it's a power source that fuels humanity in many ways. It has to be, in some manner, multifunctional.

Lastly, with regards to Weiss' glyph, it appears to be utilized as a way for her to use Dust in creative ways without the training both Glynda and Cinder appears to have. Of course, she still needs a Dust conductor for that.

So if you think about it, Weiss is actually a natural-born specialist in Dust sorcery.

Actually, that proposes an interesting question. Does your semblance determine your specialty?