Also with wands, you need only one formula, “magic wand” to craft endless, reasonably priced items that can grant every spell in the game.
I was under the impression that you needed a separate formula for each level of an item that has multiple versions at different levels. So that would be 1 formula per level for "magic wand" - which is still efficient compared to 1 formula per specific wand.
You still need a casting of the exact spell on the wand to be able to craft the wand, and you can only use a wand if you have the spell on your spell list (or Trick it), limiting their utility somewhat. Wands are still great, though.