[JimMorrison]

Well gem cost reduction means the most in summons - and maybe got cost reduced and/or # summoned increased. So in those cases it's more just about making the spells gem effective, since all summons are potentially useful, just in vanilla many are neither gem nor time efficient.

I do think that tweaking the costs of unique artifacts is a bit silly though, except maybe to raise the cost of some to reflect their perceived value.