Isn't that basically what bitcoin is?
No, it's not. Bitcoin is not just some random stuff from the internet. It has peculiar features which make it coveted.
We can hardly buy anything with it. We just give it value for the sake of giving it value.
Yes, you can hardly buy anything with it. You know why? Because people would rather keep it than spend it. However, despite Bitcoin not an acceptable currency in most parts of the world, you can actually buy a coffee with it, and a slice of pizza, a burger, a house, and a Lambo.
As to its value, just like anything which has value, even a rock, there must be certain features which give it value. The varying values attached to different kinds of rocks would differ in terms of how common they are, their physical qualities, chemical composition, and so on.
Matter of fact, let's do just that for the heck of it, see how far we can go with it. I'll pick up a rock and call it Akorn and put it up for $10. I'll buy it back for $10 and let's see how much it'd be worth by the end of the year.
Why not start with this experiment? Let's see how this will turn out.