Bitcoin is like a dollar, only in the cryptocurrency world, well, it is worth an order of magnitude higher)
Well, another thing that can be said is that they invest in it and sell it and buy it. And this keeps the market going
This is a really bad example. You can also buy/sell(exchange) pretty much all fiat currencies. One of the biggest differences between bitcoin and the dollar when talking about value is that bitcoin's total supply can't be inflated at will like how Jerome Powell of the federal reserve is going full on
BRRR[1] on the US dollar.
[1]
https://brrr.money/