That might be it. They might use it to detect if someone is pasting a password in vs typing one in. Which might help identify against bots / attackers stealing

That might be it. They might use it to detect if someone is pasting a password in vs typing one in. Which might help identify against bots / attackers stealing someone's ebay account. Which would explain why Ebay would be secretive. Because the detection is easily mitigated if attackers become aware of the detection.