Do class or subclass features that relate to spellcasting apply when producing a spell's effect from an Artificer's Spell-Storing Item?

Question

In my recent question about a homebrewed Artificer subclass, I was asked in a comment how one of the abilities that modifies spellcasting would interact with casting spells stored within a my subclass's variant version of the Spell-Storing Item feature that all Artificers get. I'd not considered it before, but I suspect it should work the same as a normal spell cast from a normal Spell-Storing Item.

But as it turns out, I'm not actually sure how that works for normal Artificers either. The relevant rules text for the Spell-Storing Item feature says (from Eberron: Rising from the Last War, page 58, and the latest version of Wayfinder's Guide to Eberron, p. 179-180) says:

While holding the object, a creature can take an action to produce the spell's effect from it, using your spellcasting ability modifier. If the spell requires concentration, the creature must concentrate.

Notable in that rules text is that it does not say that the creature using the object casts the spell, only that it produces the spell's effect. This seems relevant because the top voted answers to this previous question seem to mostly attach to the "cast" terminology used by most magical items that grant extra spells.

In combination with the answers to that question, it seems like the different language (not using "cast") may mean that using a Spell-Storing Item isn't spellcasting, and so no feature that modifies spellcasting will apply. But there's enough ambiguity that I want to ask about it here.

Do an artificer's spellcasting-related features apply to spells they store in an item? Do spellcasting-related features of the creature using the Spell-Storing Item (which may or may not be the Artificer themself) apply?

For a concrete example, if an Artillerist stores Scorching Ray in a wand, staff or rod that they had previously made their Arcane Firearm, would they get an get an extra d8 to add to one of the spell's damage rolls when they use the stored spell?

Answer 1

The spell is never cast; "cast a spell" features don't apply

Specifically, the Artificer never casts the spell. They only choose one to store in the item. Thus any of the Artificer's features like Arcane Firearm don't apply because the Artificer doesn't cast the spell.

The user never casts the spell either. They merely use the Use an Object^† action to produce the spell's effects. They don't cast it and don't get to modify it with their features which care about them casting a spell.

This is perhaps most comparable to certain potions which also bring a spells effect into being without it being cast, eg. potion of speed which apply the effects of haste without any creature (or other entity) casting the spell.

---

†: Clarified as such in the Sage Advice Compendium. Without defining it as such it would be a special, unnamed action or a Use a Magic Item action if using the definition of the Essentials Kit. Either way, it is not the Cast a Spell action.