The backstory (I worked at ebay in 2000) is that Billpoint (ebay Payments) was an ebay-Wells Fargo joint venture with a good CSR staff but no marketing funding and limited ebay integration. (I was laughed at when I asked if there was a mktg. budget for a billboard, or anything else.)
ebay used ebay Payments to learn about payment risk mgmt., then when they were comfortable bought Paypal.