Art is a mode that lets familiar things be portrayed in a way that connects them meaningfully. It's the imposition of this meaning that makes art pleasing, because coherence is created where there wasn't any before. For example, a flower can be made to look joyful, even though we don't think flowers can experience joy. A novel can suggest a whole alternate universe, even if it sketches only a few elements vividly enough. Art stimulates wonder, and therefore the consumption of art is an antidote to boredom and helplessness.
If you build a work of art with multiple modes (stories, visual imagery, music) and give it the widest possible scope, you get a mythology and culture. If you go a step further and take this work seriously, i.e. on some level believe it literally, it becomes a religion. (Though this is oversimplified, because a religion has to have normative elements too.)
What I'm suggesting is that religion fills exactly the same function as art does, though on a more directly personal level: it provides a sense of comfort because it offers a framework in which things in a person's life can be seen to fit in with the world as a whole. But I am also suggesting that a religion is nothing more than what art is -- a model or representation, not something that has independent reality or truth.
So, I'm not opposed to the adoption and practice of a religion, per se. But because mistreating models (like, confusing the map with the territory) can result in problems, I think it is probably better to recognize a religion for what it is. The only question this raises for me is, can something still be a religion -- and still be effective at what its users want it to achieve -- if it is not literally believed in?