It's really not very complicated when you get down to it.
First, all items in an economy respond to supply and demand. If there is zero demand there will be zero supply and thus no price. But for any amount of demand above zero there is a price, and to the extent demand exceeds supply price rises until equilibrium is established, either by it simply costing more or additional supply showing up as there's incentive to provide it. The opposite is also true.
The problem with so-called cryptocurrencies is that they have zero inherent value of any sort. That is, the fact that I can solve a mathematical problem and prove I did through a cryptographic signature doesn't have value; there is no utility, per-se, in doing that. Leaving aside that all such designs are inherently and intentionally ponzi schemes (that is, the "founders" always get the first of whatever it is at zero cost or nearly zero, then sell them to others at ever-higher prices) if anyone can use leverage without prior disclosure and thus become an emitter of credit into the stream they can move the price in either direction on command.
Of course their benefit and thus, for most, their motivation, is to move it higher.
But what if there the alleged "dollar" exchanged and thus which set the demand level doesn't actually exist?
If I can take a customer's "funds" and blow them on something else then until and unless I am forced to immediately remove that from the so-called "cryptomarket" where it was I have in fact emitted more dollars in the context of the cryptocurrency. The problem at its core is that I had no legitimate way to do that and thus the alleged "demand" -- and price response to it -- is a fraud. In the United States banks have an allegedly limited license to do this, that is, it is legitimate, and so does Congress through deficit spending.
Nobody else, however, holds the power to do so in a legal fashion yet the common theme is that it keeps being exposed.
You must therefore assume that all of the alleged "value" of said crypto "assets" is in fact nothing more than smoke.
Because if it was possible to make a reasonable return running an exchange without doing this -- that is, the fees charged for the service covered costs plus a profit -- then those doing it legitimately would be VERY interested in finding and outing every scam immediately. The reason for that is obvious: The scammer operates with what amounts to a digital printing press and the non-scammer does not; ergo the honest operator cannot compete in such a market as they will always lose to the scammer.
The facts, however, are that the so-called "mainstream" exchanges are not diligently looking for and exposing the frauds and the reason why not is transparent: They profit from it too even if they don't personally engage in it.
But if you profit from a scam even if you don't engage in it then you must expect that there will always be said scam and worse, since during the time it is unexposed there's nobody interested in stopping it there is no pushback to put a stop to it and in fact that takes over as the largest, if not the only mechanism by which price actually moves.
In other words ex the scamming the "value" of said "token" is, for all intents and purposes, zero.