How Many +1 Arrows Do You Make At One Time?

[kreynolds]

1) A wand with 1 charge costs less than a corresponding scroll.

Sure, but you can't scribe a fireball spell into your spellbook from a single charge wand of fireball.

2) Spell trigger items are cooler than spell completion items. Easier to use, for one.

But you can't do anything else with them (such as scribing spells), and having multiple spells on a wondrous item version of a wand gets really expensive.