OK so Tether went from 83bn to 73bn... what's the big deal? It's not like LUNA.
If $10B was pulled out, that was into actual US dollars or equivalent, meaning they now have $70B backed up by $30B. If another $10B drains in the next week, it'll be $60B vs $20B. This incentivizes other holders of Tether to also pull out so they're not left holding the bag (= Tether's stash of dodgy loans etc), basically kicking off a slow-motion version of the same death spiral that we saw for UST/LUNA, until Tether runs out of assets and the whole crypto economy goes poof.