Therefore, since there is cost to believing in a deity, you may as well believe.
There are numerous holes in this theory, the most obvious being that there are thousands of deities and you have to be sure to pick the right one because most of them don't like each other.
However there is another hole in this idea of Pascal's. Simply put, there is a huge cost to having religion. Don't believe me? Look at the monergism website. (It's okay, I know it has "gism" in the title, but it's completely safe for work) What is Monergism? Quoth I, Monergism is:
The view that the Holy Spirit is the only agent who effects regeneration of Christians. It is in contrast with synergism, the view that there is a cooperation between the divine and the human in the regeneration process.
Now look at that absolutely monumental website, entirely dedicated to this miniscule portion of Christian belief. Think of all of the intellectual time spent by these people rationalizing this tiny schism of Christian doctrine. Just gaze in rapt fascination at the sheer insanity of it all.
Now tell me again how the premise of Pascal's Wager, that "there is no cost to believing", is an accurate depiction of how people practice religion. Imagine how much better off our society would be if all of the historical church figures who had been indoctrinated in to this nonsense and therefore spent their mental power on it had instead spent their time refining our understand of the natural universe.
Imagine how far we would have progressed by now. Instead we have centuries of writings and examinations on whether an imaginary man will forgive our crimes based on our interactions with a ghost or based solely on the power of the ghost.