I think it should be pointed out of the realm of Heroes; since the Undead units in the army still crumble due to General death it should be a riskier thing if you want to use this for large amounts of Scrolling. On a Hero, unless you're horrendously lucky on failing 2+ to wound rolls, you'll only essentially get 2 Dispel Scrolls and you'll lose your caster at the end of that. I'd just take two and be done with it at that point, as it'd be too much trouble to cast rituals on myself each time I used a scroll. Also, I can't see a Zenith Prince carrying one of these. Should be wizard-only.
That raises an interesting question: Will we have a specific Hierophant like in Tomb Kings? In Vampire Counts it never showed up because your Vampire will always be a Wizard, but in here you could have a Zenith Prince as your general, but since he isn't a Wizard it doesn't make sense for the Undead in the army to crumble if he dies. We could either have a General-Hierophant like in Tomb Kings (Dread Lord/Zenith Prince would be General, Whateveritscalled and DoN would be Hierophant, Undead would only crumble if Hierophant died) or we could just restrict it that only Wizards could be the Generals, and have normal VC crumbling.