Moneyball gets a bad rap because that's what Liverpool said they were doing when they spent 20 million on Stewart Downing.
The principle, as I understand it, is that scouts looking at players can be misled by things that aren't actually important. Players who 'look the part' but don't actually have what it takes.
So if you want to get a bargain it can be useful to check out players stats and see if you can't pick up a player who nobody else wants cos he's from azerbaijan or has a drinking problem or for whatever reason puts off the scouts but does it on the pitch.
Which is a sound strategy. The players you're looking for might not be better than the ones all the scouts want but if there's no competition they will at least be cheaper.
Liverpool, being the geniuses they are, looked into the stats and picked out four or five players who nobody else fancied but the stats made look good. And then told their guys to go get them.
Except people saw them coming and just raised their prices and because liverpool wanted all of their list they ended up paying stupid prices for not very good players. Which completely missed the whole point of trying to buy players noone else wanted in the first place.
Great stuff, really.