The questions are: (1) are they legit? (Do they have the underlying assets?) (2) do the underlying assets collapse in value, (3) can they afford to keep in operation through a crisis and (4) what liabilities do they face from money launderers, tax evaders and the like using their platform?
If the assets are BTC and ETH and the values float then variations in value just happen. If they are stable coins people are going to mad if a $1.00 coin is worth just $0.95 and you will really have a run.
Ordinary stockbrokers can break down and be unable to sell your stock for you, that is why the SIPC was formed in the 1960s crash. Bin ace is also facing big trouble because it has dodgy customers, banks really hate their KYC responsibilities because they’d rather not ask what customers are doing but in a world where the Republicans, Tories, and similar parties won’t let governments raise taxes it is all they can do to make sure they collect the taxes they are owed.