The significance of the Big Bang theory is that it answers the question about when certain aspects of our universe "came into existence".
Once it is established that these aspects of our universe came into existence, we can identify high level characteristics of the causal agent based on what was caused to come into existence.
For example, as we have already discussed, eternality is a fundamental characteristic of anything that is able to bring the fabric of space and time into existence.
The Big Bang Theory also indicates that the laws of physics as we understand them came to work sometime after the fabric of space and time came into existence.
Since we know from experience that it takes intelligence to create computer and mathematical models for the laws of physics, then we can infer that whatever caused the laws of physics as we understand them to work the way they do in our universe is at least more intelligent than those who create mathematical and computer models to represent how the laws of physics work.
So by examining what happened during the Big Bang we can infer the existence of...
- a causal agent that is eternal
- a causal agent that is intelligent