One reason that I use PayPal is that I can avoid foreign currency conversion fees (I only pay for stuff; I don't sell it). If I pay a vendor in another country with MasterCard or Visa, those card services charge a fee for converting. So, I pay via Discover with PayPal and don't incur that fee. (AFAIK, Discover doesn't do foreign transactions directly.)
Also, in my (thankfully) few disputes with vendors, PayPal has always resolved the issue promptly and to my satisfaction. BTW, I do not maintain a cash balance with PayPal nor do I give it access to my bank account.