PayPal has a history of acting like a bank and withholding money from businesses if they don't like it (as well as keep the money).
Literally stories from 2010 telling people to stop using PayPal for e-commerce for that reason.
Pro: they are great for consumers.
My own personal beef with PayPal was when I sold a game console and the buyer paid using PayPal, then try to do a chargeback after receiving it. PayPal ignored my evidence and when I filed a police report and started a small claims court procedure, they relented. Which is kinda nice honestly if you're into scamming.