Signatures do have similar problems to certificates. But Gemini doesn't avoid them either and often recommends TOFU certificates. I think the comment's point was that digital signatures ensure identity but are unsuitable for e-commerce, a leading source of enshittification.
Bit-level skeuomorphism! And since NUL is zero, does that mean the program ends wherever you stop punching? I've never used punch cards so I don't know how things were organized.
Town, outside, and dungeon represent decreasing levels of safety. In most games, players want a clear indication of how much danger they are in just walking around. Some games, like Dark Souls, do blur these lines. I think it would be easy to go overboard.
This strikes me as one of those things that sounds better on paper than in practice.