I checked out a great video yesterday which showed images captured by a journalist who was covering WWII and D-Day, narrated by that same journalist (unsure of name but I'll post the link) sometime in the 70s. At one point there is footage of a plane being shot down, and he explains that such footage came from gun triggered cameras in order to document kills. According to the narrator, however, these films were taken for more than just documentation or training. He claims thet were the only way to have a confirmed kill during the war. I found little the corroborate or disprove the claim on the wikapedia page for WWII gun cameras, which is a short article. Confusingly, the wikapedia article also only mentions their usage by the luftwaffe, whereas the journalist had been covering the allied offensive. Were they used the same way on both sides? Is this narrator correct that a kill could only be confirmed with hard footage? I would love to know now, it is something I had not even known about until now.

https://youtu.be/8dXDl60fLdo (24:40 is where he makes these claims)