Artificers are not spellcasters, so Practiced Spellcaster does not benefit them at all.
But even if an artificer could benefit from Practiced Spellcaster, I would say that it doesn't affect an artificer's effective caster level for purposes of item creation, based on this: "For purposes of meeting item prerequisites, an artificer’s effective caster level equals his artificer level +2. If the item duplicates a spell effect, however, it uses the artificer’s actual level as its caster level."
The effective caster level is based on artificer level, not caster level. Practiced Spellcaster doesn't increase your artificer level, it increases your caster level; therefore, it would not help.