So I wouldn't call it a bruteforce tool unlike BitCrack; I'd stick with:
Vanitygen is a command-line vanity bitcoin address generator.
It is true but that is simply because it is not possible to crack a normal bitcoin adress. Not with vanitygen and also not with bitcrack. If it would be possible then we would have already seen some exchange wallets getting cleared out. In any case both tools are for a different purpose.