Everyone has a belief system whether they choose to acknowledge it or not. The human mind is a “belief factory,” we are constantly observing our world, inferring things about it, and choosing what to do with this knowledge. A lot of recent psychology research over the years has demonstrated that our minds are incredibly prone to error and bias. When we perceive things, we make a representation of them in our mind, but the representation is never perfect and it often is reshaped to be congruent with our current beliefs. Normally this is done subconsciously and we don't even notice or realize it is taking place.
Beliefs form in our minds to minimize our surprise about the world, or simply put, to explain things we don't understand. The prevailing thinking holds that people develop delusions to predict how events in their lives will occur — just as Pavlov's dog learned to predict that the sound of a bell ringing meant dinnertime was imminent. Occasionally humans update their beliefs when what they predict doesn't match what they actually experience, but not as often as one might expect. It takes less energy in the brain to confabulate or spin-doctor the reason for the mismatch than it does to rebuild the belief system.
Tests and studies show that delusions often appear to override the evidence of the senses. These study results demonstrate and confirm findings from previous studies that delusional individuals have less stable perceptions of the world. This is huge. Everyone can have delusions about anything, but once the belief is established, it shapes the perception so that it complies with the expectation, and changes the reality of the individual.
Nevertheless, I think spiritual beliefs can serve a purpose, even if they may be totally unfounded or illogical. If it brings a person comfort, or makes their life easier in some way, then it is beneficial. I believe that something has always existed in some sort of energy before the big bang, because it is scientifically illogical and physically impossible (As far as we know) to get something from nothing. Whatever that something was or is no one can know, even though many claim to. Personally, I enjoy a spiritual connection or syncing to that energy when in nature, but it is solely based on experience, and I don't claim to be able to prove any of it, but it is deeply soul satisfying, so it remains part of my life.