If it’s anything like Adobe eSign, the MAC and IP Addresses are added to the audit trail along with all your actions using the mouse to sign, as evidence that the signing action took place.
As for authenticating the signers identity, having access to the e-mail account (which presumably was previously verified as belonging to the signing party) is definitely a means of authentication, albeit with a low level of security. I guess for the notary this is sufficient.
Docusign does provide higher levels of authentication, such as verification using photo ids and such:
https://www.docusign.com/products/identify
Identify your way
DocuSign Identify has a spectrum of choices for organizations that need to identify signers beyond the standard practice of clicking an emailed link.
DocuSign ID Verification is fully integrated with DocuSign eSignature, enabling customers to securely verify signers’ identities prior to accessing the agreement. DocuSign ID Verification supports government photo IDs and European eIDs by analyzing the document security features and matching the name on the agreement against the name on the ID. After a successful verification, the signer can view the agreement and sign as usual.
This latter method of authentication is probably required for more sensitive signings, such as for opening a bank account.