While I generally agree with the first two answers you got to this question, I am not sure how well they answered your question. They note that gold has been used as money in the past, which means it was considered valuable in the past, but they do not really say why gold was used as money in the past.
Gold has several characteristics that made it a good choice for money.
(1) Until the atomic bomb was invented, nothing on Earth could create or destroy gold. Gold does not oxidize (rust) or react with other compounds. It is inert.
(2) While gold is rare, it is not too rare. There is enough available to make it practical to use for money.
(3) A piece of gold can easily be divided into smaller pieces and smaller pieces can easily be combined into a larger piece.
(4) All gold is equal. One gold bar is worth the same amount as any other gold bar of the same weight, while one half-carat diamond may be worth much more than another half-carat diamond due to difference in cut, clarity, etc.
(5) Gold is easy to handle and store.
(6) It certainly does not hurt that gold is shiny and attractive to the human eye.
<<<if the whole world gets thrown into anarchy for example, what are you really gonna be seeking? Gold bars, or beef/water/flour/grain/etc? I can eat beef, I can't eat gold.>>>
Actually, I'd like some of both. If that kind of anarchy came about, what do you think would be easier to hide, gold of cattle? If you couldn't hide it, you might not be able to keep it.
<<<Well if there's ever a major world disaster, that pushes many people into starvation and the like, doesn't gold become absolutely useless there? Wouldn't beef for example, be the new "gold standard"?>>>
I'm not sure what kind of a "world disaster" you are thinking about. Humans can eat a lot of different things to stay alive, including wild animals, many wild plants and bugs. If a disaster wiped out all these things it probably would have wiped out humans as well. If it didn't wipe out humans, cannibalism could always provide an alternative food source. The person who refused to share his beef might become the next meal.