> It approximates the total amount of wealth currently held in the form of a particular crypto,

I don't see how it does anything of the sort.

* It's not the amount that was put in to it

* It's not the amount you could get out of it

It's a number that's easy to calculate and gets headlines, but I can't see what else it's good for in practical terms.

Perhaps with a tiny altcoin it would be worth 51%ing it. But for anything larger, or for an ICO token? What does this number actually do?

Say there's a crypto asset that isn't getting headlines. Its market cap is $100 million. Just knowing that, what do you know about the crypto?