User blog comment:StrategicMagic/Vayne - Carry? Yes. AD? No./@comment-5052127-20120824005131

Itemizing around one ability like that is usually never good, in the case of silver bolts, it's really there just to enhance whatever AS you would normally get as a carry, not to make it viable to focus your entire build around AS. Not to say it CAN'T work, but it is definitely not the most damaging, efficient build for her. If anything, I'd get an extra AS item later on to help that ability do more damage, but not base my core items on it.

Kind of the same way that itemizing just around WW's ult doesn't really work as well as a normal build for him... It LOOKS good: "wow, TONS of ult damage!"... but it ends up being really situational and not helping him as much of the time as a normal build.