If they pay so much, why am I not going to throw some money into my Paypal account and keep it there?

First, Paypal has a history of "freezing" accounts for no reason. Back in 2001, I had an account frozen and all of my funds were frozen as well. I couldn't withdraw my money or accept any either. They asked me to send them information about me. It's been so long I forgot what they wanted, but probably a copy of my state issued drivers liscene and a copy of a credit card, and most likely a copy of a current utility bill. I sent in everything and I never did get that account re-opened.

If you think this was a fluke case, then take a look at Paypal Sucks. It's happened to lots of other people too. I think Paypal has cleaned up its' act after being sued, so I doubt anything like that would ever happen again. eBay owns it now too so that's given me enough confidence to keep using Paypal under a new account I created soon after my first one was closed. Just how confident am I in Paypal? Well I use it to pay for my eBay purchases and receive money from my eBay sales, but as soon as I have money in there, it goes right back to my bank account.
Just a couple of months ago, I "accidently" left a few hundred dollars in my account.. I was surprised to see it earned interest, as I had forgotten Paypal offered that. I think it was 5.05% APY. Not too shabby, but not FDIC-insured, so "save" at your own risk.