Simply put, in my eyes: too many electronic fingers linked directly to my personal checking account is high risk and no good.
I believe Ebay is even more susceptible/targeted to being hacked than Paypal. Ebay only has my Amex card on file for billing as I don't trust them and Amex will fight like hell if I have a problem. Having just Paypal linked to my checking I tolerated as they are strictly a well-establish 3rd party transaction entity continually focusing on security of its main business and nothing else, whereas Ebay is busy focusing on becoming 'Amazon Junior' and reaching for 'sport shoppers' who like to buy-and-return thus forcing us hobbiests to become full-time retail stores (and forced 'on demand returns') and getting away from Ebay's original business model of individuals selling ala online 'garage sale'