I always find this argument fascinating, and I can see both sides for sure.
As a very new archer myself I have the mindset that until something fails me in some way I am going to keep hunting with what I have. I decided to shoot a fixed blade to start because I felt that a passthrough should be the goal and I don't think anyone can argue that penetration with a fixed head is better. I also didn't like the fact that mechanicals seemed to fail more even though it was rare. The thought of losing an animal because of something I may have been able to tilt in my favor sucked.
So far I have shot 1 deer, it was a complete pass through where I was able to recover the deer. To me that is a success so I will use a fixed blade broadhead next year and keep doing so until I lose an animal to a flaw or defect in the head to where I want to look for and find something better.