There are a good number of freelancers of various sorts that get paid via PayPal and only occasionally pull that money to their bank accounts to avoid the fixed fee, or even prefer to spend much of it straight from PayPal to avoid the percent fee. People also use it to send money between family members in different countries because it's often cheaper than an international wire.

It's quite easy to build up a few hundred or thousand USD worth. It feels just enough like a bank account that you think you're safe. Then...well, the internet is full of PayPal horror stories, I won't bore you with my own.