As people keep saying, benchmarks give you an idea of performance in benchmarks.
I don't think anyone is claming that a certain score in a benchmark indicates the performance in a game.
What benchmarks are useful for, however, is comparing one PC to another and measuring the changes ones makes on a single PC.
For many people, myself included, a benchmark is a toy, something to play with when overclocking to give you a quantitative figure of how much impact your overclock / tweak has made.
In this respect, Vantage is like any other benchmark - you run it, it gives you a number. You run it again after tweaking, you see a different number.
So no, I don't think Vantage is crap.
Is anyone claiming that it provides a real-world indication of games performance? If so, there is some truth in that, since it's highly likely that a PC 1 scoring higher than PC 2 will perform better in games too.
I do agree that the performance in 3DMark is not necessarily indicative of performance in a game though.