DocuSign doesn't provide anything other than convenience. Generally, in the law, either a signature must be notarized or it doesn't. Docusign isn't a notary, it's really just an electronic document courier. If the legitimacy of a signature is challenged, Docusign isn't going to hire a forensic expert to testify that John Smith was actually the person who logged in and clicked the link. All they can say is that someone with access to the link from IP address 1.1.1.1 clicked Agree.