It's not the innumerable man hours already put into it (most of the bible, if not all, has already been translated.)
It's not even the hilarious results:
Genesis 1:1 - Oh hai. In teh beginnin Ceiling Cat maded teh skiez An da Urfs, but he did not eated dem.
What really landed this site here is the unintentional hilarity that is the google ads: almost every one advertises courses to learn the bible. For some reason, I don't think that the people who visit the Lolcat Bible Project are interested in learning about the "real" bible.