Audacity: First of all, I wasn't addressing any particular aspect of evolution, but your question of why it matters if evolution occurred. The why it matters aspect---in particular, why it matters to some Christians.
Yes, it does matter to some Christians - but that has to do with specifics of how they view the pertinent Scriptures and to what extent they believe the Creation accounts to be speaking scientifically, say, as opposed to other possibilities (as to their individual take upon the theological understandings of the Jews at the time of the writings, or perhaps, symbolically, or even literally).
Audacity: So I'm a bit confused by your leap into any issue concerning the Big Bang. Secondly, I have to take issue with your notion, or implication, that the theories of the natural evolution of life are some how dependent on what happened 13.82 billion years ago. The theories of evolution only concern themselves with change, and are not interested in any first cause of life.
The REAL issue and reason we're discussing evolution on this site is related to whether a universe and life itself is possible without a Creator. So, as for the THEORIES of what took place per the processes in which life began - yes, those are a separate but clearly dependent issue. As for evolutionary processes themselves, EVERY physical thing, chemical and biological process, and condition that would allow them to be possible - all of these were entirely dependent upon what came at the beginning, as if what came at the very beginning had not burst into physical existence, exactly as they did, the processes of supposed evolution would not have been impossible, as the necessary elements, not to mention the immensely complex requirements for life to even exist, would not otherwise have been possible. So, while the details of how evolution might have worked are a separate issue, evolution itself is nonetheless a series of processes that would only have been possible due to what came first - over 10 billion years before any life existed to evolve. And so, for our purposes of argument on this board, what came first is precisely the FAR bigger deal.
Evolution arguments, as they relate to the question of God's existence, are only smoke-and-mirror diversions that avoid the much more important question of what made them possible to begin with - as NOTHING that physically exists, not time, nor space, dimension, the necessary elements, chemistries, biologies - none of those existed, and yet, in the VERY next MOMENT, they ALL did, and with unfathomable power, design, and incredible specificity of function, and all perfectly interacting together with precision and clock-like precision. Not even one aspect of supposed evolutionary processes would have been remotely possible without what IMMEDIATELY happened within moments of the Big Bang's beginning. As all of that intelligent design and functionality was IMMEDIATELY apparent a moment after the Big Bang's beginning, AND was necessary to explain EVERYTHING that followed it, 10-plus billion years later, when life began. This is the FAR bigger issue as for any God arguments! And the God question is the entire reason for this website. We can argue all day long about dependent and secondary processes. I'd rather not, as it doesn't address the central and most important question: Can a such an extraordinary and unfathomably complex universe "pop" into existence without a powerful intelligence and designer.
WHATEVER one thinks existed before the Big Bang, they must admit: 1) It was eternal - it couldn't created itself; 2) It was supremely powerful and intelligent beyond our comprehension! Because what it produced, revealed staggering design, function, and indescribable power, these elements all immediately springing into physical existence within moments of the Big Bang beginning, and they were and ARE necessary to all things that have ever physically existed.