If she cuts you off you can't cast spells the normal way.
If you can manage to tap into the Shadow Weave or perhaps siphon magical artifacts though...
I thought about that, too, that Gale might be using the Shadow Weave to cast spells.
Do I remember this correctly that you would have to either worship Shar or at least make some sort of arrangement with her to use the Shadow Weave safely?
If so, maybe Gale's interest in Shadowheart (when we first met him in early access) is a bit more than just finding her attractive.
Edit: I can't really imagine Gale as anything else but a wizard.
