So we spend more money and put these in the entire GA fleet. And you get the data you describe above, including every expletive uttered by the pilot into his microphone, including the usual final "ah £¥€#" .
So what. What are you going to do with it? How does it contribute to reducing the frequency with which GA pilots destroy perfectly good airplanes, and their lives, by merging them with terra firma?
Never said it should be required, but if it was voluntary, or helps get you a better insurance rate, then I can see value in these data points
For example, if we knew the pilot became incapacitated, then we could look back further medically to find out what incapacitated him, and maybe discover something that could help future pilots.. an autopsy may show similar thing, but even having a cockpit voice recording would give you a world of information we are missing right now. There's a reason airlines have it, and there's a reason that more and more drivers now have dash cams recording, that they voluntarily install to protect their own rear end in a crash. It always helps to know the full accident chain
Or, maybe we'll find out that he was perfectly fine and just became disoriented in IMC and was struggling to break the stall while also not hitting the ground and panic set in. In that case, that might change our training culture. I did plenty of unusual attitude recovery in IR training, but we never actually stalled it in actual IMC, maybe maneuvers like that need to be practiced in a simulator. I'm not saying they should, but any data from an accident can be useful
Psychologically, there's also not much focus put on preventing panic set in during emergency situations. My training was very process-oriented and rationally based, which is good, but maybe there should be some psychological training as well.. even if it is something stupid like making the first point on all emergency checklists "don't panic" - that might habitualize your response and in a real emergency, to know not to panic and follow your training