Yes, while it dosnt seem too useful it can be very nasty against certain enemies (try b9d9 Marignon flagelants against jotun/SC heavy enemies, the enemies are cursed and the flagelants have 2 attacks with a 350% chance of causing an affliction(before curse effect is added))
It's also probably better to use with a lot of weak sacreds as opposed to a few strong ones. Although it's not really a bless I'd shoot for past B6 anyway, just the strength boost is better IMO.
...so blood9 bless is oh-so-powerful that it needs a MR check, even if none of the others do ? And Curse spell itself doesn't grant you a MR check. I guess MR check adds up to flavor.
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