Spell Dark Skies

[GrudgeBringer]

Does the spell dark skies actually deserve looking at?

As I read the description, it says its more of a Morale issue for opposing armies than what I thought it was going to be .

I thought that it would be more like The spell that afflicts the world with Darkness but only affects your nation.

So, as it is a Global, I wonder if anyone has used it and is it worth the time and gems?

Thanks for any info