BLU's raise spell requires you to clear all of Masked Carnivale up to floor 30.
You can't easily clear Masked Carnivale without spells learned from trials.
To get these spells, you need to use party finder, and once you get in, almost certainly nobody will have Raise (since you needed to complete masked carnivale to get it!)
A few people will die, and these people won't get the spell, and they can't be raised. The party will disband afterwards unless its comprised entirely of saintly people, which from my experience has never happened. The people that died will sit there looking at their corpses while everyone learns the spell, and will have a horrible experience.
There's no reason for the absolutely ridiculous requirement for the BLU raise spell, considering CNJ gets it at lv. 12. Square wants us to form entire parties of BLU to do content, and yet gated a required spell to do this content behind finishing the content in the first place, which is aggressively bad design.