Sure, one can always look at the positive aspects of reality, and many materialists have even tried to put a positive spin on the inevitability of death without an afterlife. But it should not be surprising that what is real is not always what is most beautiful. There are a panoply of reasons not to believe things that are not true, but greater aesthetic value does not seem to be one of them. There is an aesthetic value in the idea of 'The Truth,' but I would not say that this outweighs all of the ways in which fantasy can be appealing for most people. And the 'fantasies' of which I am speaking are not completely random untruths, like "Hey, I'm gonna believe in Hobbits, because that would be cool!', but rather ideas that spring from the natural emotional experiences of humanity. They feel correct. Even if they are not.