But are we really talking about "assets" here?
Tokens, etc. are easiest to think of as securities (aka stock) generally, albeit securities in a more abstract thing than a company.
Also; stock in private companies is often not tradeable at all, but no accountant is going to call those fake.
There are multiple ways of plausibly pricing assets.
None are generally accepted that would let someone just make up a ridiculous valuation and stand up to any scrutiny, but people can always do what they want until the auditors show up anyway.
Now, whether or not this is how banks act in practice is another question. It is, perhaps, how they should act if they're being conservative, but it is likely that others will swoop in and often enough grab that interest for themselves. And in the rate environment we've been in until very recently, those are likely the banks that have managed to survive in many cases.
The fundamentals for your ponzi coins are so bad they might as well be worth zero, so why would that insignificant value difference matter anyway?
Crypto tokens are unable to generate revenue.