Unnatural Bane shard?

So, quick question - is there any reason not to use an Unnatural Bane shard (which affects Undead, Aberrations and Monstrous Humanoids), and does not require a Soul Gem, rather than go to the trouble of acquiring a Soul Gem and crafting one of those other 3 bane shards specifically?

At face value, it strikes me that the 3-in-1 shard, plus the ready ingredients, is a no-brainer. Am I missing anything? :confused:

TIA!

If you don't have a ton of caravan logbooks or marks of the keeper, and you have a warlock, wizard or sorcerer who can easily farm up soul gems as needed, it's reasonable to go with undead bane instead of unnatural.

Otherwise, no, unnatural bane is clearly superior in every way. Especially since it's always nice to have a silver undead beater for vampires, meaning your unnatural bane version would be perfect for werewolves.

Or, heck, go with metalline of unnatural bane with a ghostbane augment and it's got you covered six ways to sunday:
- Vampire DR
- Werewolf DR
- Mindflayer DR
- Ghost Touch

Win!