After reading through some lore I was originally confused on why it seems Azura is believed to be a 'good' Daedra, while it seemed in most of what I read she was more conniving than anything. After finding out that 'However, although she is never overtly deceitful, the way Azura always gets what she desires in the end' my question is what would Azura ever have to benefit from destroying the Red tower?

Getting back at the Tribunal. And the entire Dunmer people.

I think it's also insinuated that she did it on behalf of Dagon, that they had some sort of deal.