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?