The whole reason PayPal exists as a separate entity from eBay is that people don't trust eBay to store credit card information. I'm not going to give eBay permission to store my credit card information or provide it with direct access into my PayPal account, because I don't trust eBay to store that information securely--and eBay's terms of use explicitly indemnify it from responsibility for harms from security breaches (including loss of my payment information).
Rather than addressing the actual issues with the platform (e.g., that reputational scores are somehow insufficient for sellers, though they were designed for exactly this issue), eBay is just trying to force users to comply. All that does is push reputable buyers to other platforms. That's exactly what I just did. I went to make an offer, got a message from eBay that indicated, "We don't trust you, schmuck. Trust us with your PayPal access," so I left and bought all of the items in my cart elsewhere. I don't need the risk or the hassle.
Worse, eBay doesn't even respect users enough to link to explanations of how this sort of information is protected. It's yet another in a long list of increasingly and needlessly aggravating blunders from eBay.
