If your team include a lot of caster, Noctural sect will be a great help for them. Cause the less damage they directly take, the less they will be interrupted.
In addition, i never saw a Hot make a critical, but if you do a critical blow with Aspected skill in Noctural sect, it's almost like you double the shield power. And a protection is never a waste like regen can be.

And then, in dungeon, some boss use heavy skill on random target. You're usually informed by a target that appear above this player. You can avoid a deadly shot on him thanks to the noctural effect. The regen effect of diurn sect is not usefull to a dead one.