Money used to be gold. It had mass; it had a color; it had an atomic number; it had physical characteristics that were immutable. If you stored it somewhere that's where it was. When you owned it, you had it in your possession and you knew where that was and what it looked like and what you could buy with it and how you could transact with it. All these characteristics were governed by the laws of physical reality.
Money now has no form or mass: it has use in the physical world but it does not exist in the physical world.
Money is now only an idea. And no idea has any objective reality. Not even mathematics. Every idea is subject to contradictions, (politely - or eruditely -called paradoxes). Xeno's paradoxes show the contradictions between the idea of space and time and the actuality of space and time. Russel's paradox shows that even the logic of basic mathematics breaks down under close scrutiny.
Money now has only the properties that the Enforcing Institution that issues it decides it should have. And those properties constantly change. And they are enforced differently for different participants.
For example money is issued for free to Banks. But not to the clients of banks. Money can be lent out or borrowed but the rules of who has to pay back loans is vastly different for an institution or individual that is considered too big to fail and for an institution or individual that isn't.
In fact the rules of who is taxed and how they are taxed and and who can transact and how they can transact are vastly different for different members of thre same society and these rules are constantly changing.
Since money is only an idea, you can not even store\own your own money. You must have it stored in theory in an institution that plays by different money rules than you do. When it comes time to access your money it may or may not be accessible depending on the shifting rules of the instituions that store it for you. The same for when you invest it. And how you invest it.
In other words money as an idea is subject to all the contradictions (or paradoxes) that all ideas are subject to.
And that is an enromous benefit for the the Institutions that issue and control money and those closest to these institutions and an enormous detriment to everyone else.
The truth is this experiment with taking money out of the pbysical world and making only and idea that is subject to the whims of those that control its issuance is only about forty years old. For all of human history until just a few years ago money existed in the physical world, and was subject to the laws that governed physical reality: some of which are unchanging and immutable.
And so far money as an idea is not going that well. It's all ending up in a few hands nearest the issuing institutions.
Everyone else's money is being slowly confiscated through inflation, which is just the process by which more and more money is issued to fewer and fewer participants, so everything in the real world costs more and more for everyone else.
If that makes you uncomforatble perhaps you should consider storing part of your wealth in real things that exist in the real world and are subject to the laws that govern physical reality.