This is Pascal's wager. Like others here have pointed out, you could make up an unlimited number of metaphysical claims about the universe that would have dire consequences if we don't take them seriously. The two main flaws with these line of reasoning are 1. We have no evidence whatsoever that the claim is true (there is no evidence that the Christian God, or any other gods, exist). 2. There is a penalty imposed on us for "believing" this claim since we would have to radically adjust our lives / world view to conform to this (going to church, donating to churches/charities, following a moral code imposed by Christianity etc. etc.; it is a huge cost).
Simple example, I could make the claim that the world will end in 24 hours unless everyone reading this sends me $100. If I'm wrong, you are only losing $100, and if I'm right you will save the world by sending me money. I don't think anyone is going to send me $100 though...
