15/5 gets you 9th level spell slots, so that's nice. I don't have the book so idk what Artificer gets at 6th level, but a 6/14 split would also net you 9th level spell slots but no 8th level spells.

As for practical value, idk if Artificer 5 is worth it honestly. Sure you get INT to attack and an Extra Attack, but tbh I'd rather go for something like Crossbow Expert to get another attack per turn, or just use Bigby's Hand/Flaming Sphere. The Agathys/Ward combo is cool, but I found in Abjuration Wizard play that my ward was often drained by a single attack, so it's not really a sustainable tactic without the Deep Gnome feat or Warlock's Armor of Shadows invocation.