I am part of the Gun Runner club, and have had P38 can openers on key rings for the last fifty years. I was first introduced to the P38 in 1961/62 as a smoke chaser. In those days we would hike into lightning fires with a Type A or B Lightning Pack contain four boxes of rations, one meal each. These were in the days long before the MRE came out. Part of my personnel gear was a pocket knife and later a pocket knife was on the daily readiness inspection form.
I have opened a few cans with a knife, including coffee cans which are rather tough. I think the post links are fitting and educational. Back in the 60’s and 70’s I have seen a lot of can food sent out to the line without a can opener. I have also been witness to the inexperience cutting themselves while opening a can with a knife, which is why a P38 is a welcome key chain accessory for the experienced outdoorsman. A first aid kit is a welcome accessory when some are using a knife to open a can.
I have opened a few cans with a Buck knife and a M7 bayonet. A few have lived a life in the woods/brush that what you carry on your back is what you have for an extended period of time. I would much rather open a can with a P38. I have also used a P38 as an emergency screw driver.

It is amazing how many people forget the can opener when they go camping.
For the last 20 years I have carried a Leatherman Wave on my belt. What takes me back to the old basic Boy Scout knife of my youth. It was and is a practical tool along with a pocket first aid kit.

REX I think you post is of value because somebody will see it and use the lesson learn to open a can of coffee or beans.