Spell description says it grants the favor of the cleric's deity to the target, and I don't think the influence of a deity should have too many limitations, practically speaking. Some, but not a lot.
I'd rule that the points can be spent on any roll that will have immediate consequences to the blessed character, but still must be declared before the roll is made. If you're in a real bad position and the Big Bad is about to pummel you, spend a few points on his attack roll (effectively a one-shot AC bonus). If you really need to make a good impression on that suspicious guard, spend a few points on a reaction roll. If you just need to escape a foe that's chasing you up a rock wall, spend a few points on their climb check. If a fellow party member is trying to break open a door to help you escape from the approaching acid slime monster, spend a couple points on his open door roll.
But again, if there's no immediate consequence to the blessed character, no help from on high. And I'd also say you'd have to know that someone is making a roll before you can ask a deity to help; no casting bless right before watch duty and telling the GM "I spend 5 points on the first stealth roll against me". Similarly, no spending points on an attack roll if you don't know it's coming, though you can still freely spend the points on your own rolls that respond to things you didn't see coming, like saves vs unseen traps, etc.
Basically, the way I read the spell, spending the points to aid a roll is basically you petitioning the deity for help with whatever you're doing. Kinda like a little mental prayer that effectively takes no time.
Last edited by Yuritau (2013-01-10 10:23:20)