I had to use of it once. A certain person that you might like to kill at one point has a ridiculous amount of resistances both to melee and magical damage. I had to use all the tricks I could find to reduce his resistances and Divine Light was one of them. It made a huge difference since spells had a high chance of success after it was used. The first spells I needed to use was debuf spells before I could use damage spells and regular attack. So don't rule it out completely...
The person in question is the wizard Arhu.
