Why bother with powerstones?

[hcobb]

Found something else that powerstones can do and manastaffs can't.

ITL page 163: "replace ST lost through spell-casting or other fatigue."

I can find no mention of staff mana doing this.

The only mention of using mana for anything is here:

ITL 148: "Each point of mana can be spent like a point of ST to power spells."

This page also mentions "The wizard must be holding or wearing the staff for it to be useful." So pay $70 to the Wizard's Guild to put five conceal spells on your fine silver dagger and then just keep it in your pocket.