Yes they want your bank number to be verified. I think you can do some limited things with just a CC. However, all you need to do is create an additional checking accout with $20 it in. Costs nothing at your bank to do this. Then, provide those details to paypal. If you need more $ in that account to buy something, simply transfer the $ from some other account into the one you created for paypal. Should there be no money in that account..the backup source is the credit card.
IMO paypal is pretty safe. The biggest problem is with dirtbags sending out mass mailings of phishing sites. Dummy look-alike paypal sites that you respond to and they get your password. Lots of people fall for this. They are identical looking. The only way you can be sure is to enter
www.paypal.com in your address bar. Never click on a link from an email taking you to paypal. The good news is that paypal covers you even if you get suckered into this deal. It takes a few weeks but you get your $ back . (It happened to me a couple years ago)
All that said....you are never completely safe...the information on the bottom of every check you write contains all the data you need to drain your account. Most merchacts that do direct pay can suck your money out just with the info on a blank check. The reason most don't ....it is a felony
That is another reason I like paypal, no merchant ever gets any personal financial info.