Single post in Account Breach incident

There is no such thing. I'll admit, I'm confused as to why people sell ZC for USD in the first place. Like... selling it cheaper than the site does makes no sense because you're deliberately losing value (you have 100 ZC, you sell it for less than £1 - and yes, $1 USD is MUCH LESS than £1). Selling it for more than the site does makes no sense because the buyer can just buy from the site. Seriously... why do people buy/sell ZC for PayPal when it's a bad deal for everyone involved? EDIT: Explanations from users have been very helpful to my understanding of this query. Thank you! ^^