Reserve requirements are about how much cash they must keep as a percentage of their assets, where capital requirements (which are non-zero) are more relevant to the fraction held in fractional reserve systems and are about ensuring solvency.
As FTX showed, if most of your capital loses its value then you are insolvent. The banking system is just a little more insecure than it was with fractional reserves.
I'm happy to be shown that I'm wrong, since I am not an expert.
Further, from the announcement that lead to this, it seems that the reserve requirement is zero because the mechanisms have changed. The reserve requirements appear to have applied specifically to reserve accounts held centrally at the federal reserve.
To me this looks very much like a ‘scare’ factoid that can be latched onto and shared in order to persuade people that the banking system is way more fragile than it is, and that it’s collapse is either imminent or inevitable.
OMG zero reserves! Dig a bit deeper and that’s partially true and perhaps not all that important, and represents a technical change in operations rather than the massive risk increase it gets portrayed as.
It's an interesting double standard.
Nobody expects that their money deposited into a savings account is going to sit in a bank vault until it’s time to go pick it up — they know the bank is going to loan it out and pocket the difference between what they charge the borrower and what they pay in interest.
Checking accounts are different in that they should have the money on hand to settle whatever spending the customers get up to but instead they practice fractional reserve deposits with a central bank to bail them out if needed.
The difference here is the crypto bros are practicing fractional reserve without someone to bail them out so depositors just get screwed.