In Mother Russia, can opens you!
As much as I've enjoyed simple Soviet technology in past decades, the question begs, why be caught without a P-38 (which we called a John Wayne in the USMC) or the larger P-51?
They're so inexpensive, that one can literally buy a few at any local Army & Navy store for very little money. It can easily be attached to any piece of gear.
For the sake of brevity, I'll just link an already typed up list another's thought of for uses of the ubiquitous U.S. Military surplus can openers.
43 Uses for a P-38 | Adventure-Some
It is a good topic though! The lid from the video also lends itself to being fashioned into an improvised cutting device if one should find themselves without any "survival kit."
In a self reliance situation, one should have a basic five "C" kit, and each piece should be dependable.
Cutting device (Knife 2.5" - 4")
Combustion device (flint/steel or ferro rod)
Covering device (5'x7' tarp at the very least)
Container (stainless steel canteen)
Cordage (quite a few yards of bank line, paracord for improvised shelter building and other uses, etc.)
One can throw the aforementioned kit together for a few bucks. Many will already have items at home they could use in a pinch. The problem is, all those items require some practical knowledge on how to use them...
Cheers,
bolillo