Physical gods have access to blue stone for DoT on abilities, and malice for DoT on AA(crits), where is our DoT for magical gods? Sure everyone can grab mystical mail but that isn't the same....
It'd be nice for the invisibility counter. As is, if you are playing a magical god, you can only really hope you've got DoT in your kit(and that is is easily applied) whereas physical gods have options for both abilities AND basics. They might not always want to build them, but they are there at least.
It doesn't have to be a powerful late game item, even just a starter like bluestone would be fine.