Money is a representation of value created or received. It can take many forms, but the most prevalent manifestation is as fiat currency issued by governments. What does that even mean? Basically, it means that most money is a way to pay for something without exchanging anything that is in its own right valuable. You can't really do anything with some money except exchange it for other things. That's "fiat." The reason you can do that is: the government says that that is what the money is for.
Some money is physically around. This kind of money might be coins or printed slips of paper or plastic. Some money is just numbers that live inside computers or simple paper records. This money mostly moves around via channels that either literally are or are adjacent to the internet.
Storing value in something portable or easy to gesture at sure is convenient! But there are some drawbacks. When you take the idea of being able to exchange value and put it into a form that is indefinitely replicable, exists in unknown quantities, and has no logical ties to any sort of actual value exchange, you make it possible for entire societies to replace any of their existing goals with the shared goal of producing as much money as possible. This is capitalism. A noted effect of capitalism is that it incentivizes each person to accumulate as much money as they can for themselves, which disincentivizes people to use this value-store concept to improve the living situations of anyone else, or even to take the degradation of their living situations into account while maximizing their own store of represented value. In short, societies that regard accumulating money for its own sake to be the primary purpose of work tend to actively create adverse situations for at least some people (and today, we can call that most people) in service of allowing a smaller group of people to create or collect all the money.
Historically, introducing money to economies that understood value to be a feature of the value-store itself (i.e. used non-fiat currencies) has resulted in those economies being replaced by the fiat kind, with a significant advantage given to the economic participants who first agreed to facilitate the introduction. This first-mover advantage resulted most often in subjugation of the community by the introducing party and their participating local party, and was a near-universal feature of colonialism.
Whether viewed historically or for its effects today, it's hard not to conclude that money is pretty dangerous.
